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1 //===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements extra semantic analysis beyond what is enforced
11 //  by the C type system.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Sema/SemaInternal.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/CharUnits.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/DeclObjC.h"
20 #include "clang/AST/EvaluatedExprVisitor.h"
21 #include "clang/AST/Expr.h"
22 #include "clang/AST/ExprCXX.h"
23 #include "clang/AST/ExprObjC.h"
24 #include "clang/AST/ExprOpenMP.h"
25 #include "clang/AST/StmtCXX.h"
26 #include "clang/AST/StmtObjC.h"
27 #include "clang/Analysis/Analyses/FormatString.h"
28 #include "clang/Basic/CharInfo.h"
29 #include "clang/Basic/TargetBuiltins.h"
30 #include "clang/Basic/TargetInfo.h"
31 #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
32 #include "clang/Sema/Initialization.h"
33 #include "clang/Sema/Lookup.h"
34 #include "clang/Sema/ScopeInfo.h"
35 #include "clang/Sema/Sema.h"
36 #include "llvm/ADT/STLExtras.h"
37 #include "llvm/ADT/SmallBitVector.h"
38 #include "llvm/ADT/SmallString.h"
39 #include "llvm/Support/Format.h"
40 #include "llvm/Support/Locale.h"
41 #include "llvm/Support/ConvertUTF.h"
42 #include "llvm/Support/raw_ostream.h"
43 #include <limits>
44 
45 using namespace clang;
46 using namespace sema;
47 
getLocationOfStringLiteralByte(const StringLiteral * SL,unsigned ByteNo) const48 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
49                                                     unsigned ByteNo) const {
50   return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts,
51                                Context.getTargetInfo());
52 }
53 
54 /// Checks that a call expression's argument count is the desired number.
55 /// This is useful when doing custom type-checking.  Returns true on error.
checkArgCount(Sema & S,CallExpr * call,unsigned desiredArgCount)56 static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
57   unsigned argCount = call->getNumArgs();
58   if (argCount == desiredArgCount) return false;
59 
60   if (argCount < desiredArgCount)
61     return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
62         << 0 /*function call*/ << desiredArgCount << argCount
63         << call->getSourceRange();
64 
65   // Highlight all the excess arguments.
66   SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
67                     call->getArg(argCount - 1)->getLocEnd());
68 
69   return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
70     << 0 /*function call*/ << desiredArgCount << argCount
71     << call->getArg(1)->getSourceRange();
72 }
73 
74 /// Check that the first argument to __builtin_annotation is an integer
75 /// and the second argument is a non-wide string literal.
SemaBuiltinAnnotation(Sema & S,CallExpr * TheCall)76 static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
77   if (checkArgCount(S, TheCall, 2))
78     return true;
79 
80   // First argument should be an integer.
81   Expr *ValArg = TheCall->getArg(0);
82   QualType Ty = ValArg->getType();
83   if (!Ty->isIntegerType()) {
84     S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
85       << ValArg->getSourceRange();
86     return true;
87   }
88 
89   // Second argument should be a constant string.
90   Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
91   StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
92   if (!Literal || !Literal->isAscii()) {
93     S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
94       << StrArg->getSourceRange();
95     return true;
96   }
97 
98   TheCall->setType(Ty);
99   return false;
100 }
101 
102 /// Check that the argument to __builtin_addressof is a glvalue, and set the
103 /// result type to the corresponding pointer type.
SemaBuiltinAddressof(Sema & S,CallExpr * TheCall)104 static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) {
105   if (checkArgCount(S, TheCall, 1))
106     return true;
107 
108   ExprResult Arg(TheCall->getArg(0));
109   QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart());
110   if (ResultType.isNull())
111     return true;
112 
113   TheCall->setArg(0, Arg.get());
114   TheCall->setType(ResultType);
115   return false;
116 }
117 
SemaBuiltinOverflow(Sema & S,CallExpr * TheCall)118 static bool SemaBuiltinOverflow(Sema &S, CallExpr *TheCall) {
119   if (checkArgCount(S, TheCall, 3))
120     return true;
121 
122   // First two arguments should be integers.
123   for (unsigned I = 0; I < 2; ++I) {
124     Expr *Arg = TheCall->getArg(I);
125     QualType Ty = Arg->getType();
126     if (!Ty->isIntegerType()) {
127       S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_int)
128           << Ty << Arg->getSourceRange();
129       return true;
130     }
131   }
132 
133   // Third argument should be a pointer to a non-const integer.
134   // IRGen correctly handles volatile, restrict, and address spaces, and
135   // the other qualifiers aren't possible.
136   {
137     Expr *Arg = TheCall->getArg(2);
138     QualType Ty = Arg->getType();
139     const auto *PtrTy = Ty->getAs<PointerType>();
140     if (!(PtrTy && PtrTy->getPointeeType()->isIntegerType() &&
141           !PtrTy->getPointeeType().isConstQualified())) {
142       S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_ptr_int)
143           << Ty << Arg->getSourceRange();
144       return true;
145     }
146   }
147 
148   return false;
149 }
150 
SemaBuiltinMemChkCall(Sema & S,FunctionDecl * FDecl,CallExpr * TheCall,unsigned SizeIdx,unsigned DstSizeIdx)151 static void SemaBuiltinMemChkCall(Sema &S, FunctionDecl *FDecl,
152 		                  CallExpr *TheCall, unsigned SizeIdx,
153                                   unsigned DstSizeIdx) {
154   if (TheCall->getNumArgs() <= SizeIdx ||
155       TheCall->getNumArgs() <= DstSizeIdx)
156     return;
157 
158   const Expr *SizeArg = TheCall->getArg(SizeIdx);
159   const Expr *DstSizeArg = TheCall->getArg(DstSizeIdx);
160 
161   llvm::APSInt Size, DstSize;
162 
163   // find out if both sizes are known at compile time
164   if (!SizeArg->EvaluateAsInt(Size, S.Context) ||
165       !DstSizeArg->EvaluateAsInt(DstSize, S.Context))
166     return;
167 
168   if (Size.ule(DstSize))
169     return;
170 
171   // confirmed overflow so generate the diagnostic.
172   IdentifierInfo *FnName = FDecl->getIdentifier();
173   SourceLocation SL = TheCall->getLocStart();
174   SourceRange SR = TheCall->getSourceRange();
175 
176   S.Diag(SL, diag::warn_memcpy_chk_overflow) << SR << FnName;
177 }
178 
SemaBuiltinCallWithStaticChain(Sema & S,CallExpr * BuiltinCall)179 static bool SemaBuiltinCallWithStaticChain(Sema &S, CallExpr *BuiltinCall) {
180   if (checkArgCount(S, BuiltinCall, 2))
181     return true;
182 
183   SourceLocation BuiltinLoc = BuiltinCall->getLocStart();
184   Expr *Builtin = BuiltinCall->getCallee()->IgnoreImpCasts();
185   Expr *Call = BuiltinCall->getArg(0);
186   Expr *Chain = BuiltinCall->getArg(1);
187 
188   if (Call->getStmtClass() != Stmt::CallExprClass) {
189     S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_not_call)
190         << Call->getSourceRange();
191     return true;
192   }
193 
194   auto CE = cast<CallExpr>(Call);
195   if (CE->getCallee()->getType()->isBlockPointerType()) {
196     S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_block_call)
197         << Call->getSourceRange();
198     return true;
199   }
200 
201   const Decl *TargetDecl = CE->getCalleeDecl();
202   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
203     if (FD->getBuiltinID()) {
204       S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_builtin_call)
205           << Call->getSourceRange();
206       return true;
207     }
208 
209   if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens())) {
210     S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_pdtor_call)
211         << Call->getSourceRange();
212     return true;
213   }
214 
215   ExprResult ChainResult = S.UsualUnaryConversions(Chain);
216   if (ChainResult.isInvalid())
217     return true;
218   if (!ChainResult.get()->getType()->isPointerType()) {
219     S.Diag(BuiltinLoc, diag::err_second_argument_to_cwsc_not_pointer)
220         << Chain->getSourceRange();
221     return true;
222   }
223 
224   QualType ReturnTy = CE->getCallReturnType(S.Context);
225   QualType ArgTys[2] = { ReturnTy, ChainResult.get()->getType() };
226   QualType BuiltinTy = S.Context.getFunctionType(
227       ReturnTy, ArgTys, FunctionProtoType::ExtProtoInfo());
228   QualType BuiltinPtrTy = S.Context.getPointerType(BuiltinTy);
229 
230   Builtin =
231       S.ImpCastExprToType(Builtin, BuiltinPtrTy, CK_BuiltinFnToFnPtr).get();
232 
233   BuiltinCall->setType(CE->getType());
234   BuiltinCall->setValueKind(CE->getValueKind());
235   BuiltinCall->setObjectKind(CE->getObjectKind());
236   BuiltinCall->setCallee(Builtin);
237   BuiltinCall->setArg(1, ChainResult.get());
238 
239   return false;
240 }
241 
SemaBuiltinSEHScopeCheck(Sema & SemaRef,CallExpr * TheCall,Scope::ScopeFlags NeededScopeFlags,unsigned DiagID)242 static bool SemaBuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall,
243                                      Scope::ScopeFlags NeededScopeFlags,
244                                      unsigned DiagID) {
245   // Scopes aren't available during instantiation. Fortunately, builtin
246   // functions cannot be template args so they cannot be formed through template
247   // instantiation. Therefore checking once during the parse is sufficient.
248   if (!SemaRef.ActiveTemplateInstantiations.empty())
249     return false;
250 
251   Scope *S = SemaRef.getCurScope();
252   while (S && !S->isSEHExceptScope())
253     S = S->getParent();
254   if (!S || !(S->getFlags() & NeededScopeFlags)) {
255     auto *DRE = cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
256     SemaRef.Diag(TheCall->getExprLoc(), DiagID)
257         << DRE->getDecl()->getIdentifier();
258     return true;
259   }
260 
261   return false;
262 }
263 
isBlockPointer(Expr * Arg)264 static inline bool isBlockPointer(Expr *Arg) {
265   return Arg->getType()->isBlockPointerType();
266 }
267 
268 /// OpenCL C v2.0, s6.13.17.2 - Checks that the block parameters are all local
269 /// void*, which is a requirement of device side enqueue.
checkOpenCLBlockArgs(Sema & S,Expr * BlockArg)270 static bool checkOpenCLBlockArgs(Sema &S, Expr *BlockArg) {
271   const BlockPointerType *BPT =
272       cast<BlockPointerType>(BlockArg->getType().getCanonicalType());
273   ArrayRef<QualType> Params =
274       BPT->getPointeeType()->getAs<FunctionProtoType>()->getParamTypes();
275   unsigned ArgCounter = 0;
276   bool IllegalParams = false;
277   // Iterate through the block parameters until either one is found that is not
278   // a local void*, or the block is valid.
279   for (ArrayRef<QualType>::iterator I = Params.begin(), E = Params.end();
280        I != E; ++I, ++ArgCounter) {
281     if (!(*I)->isPointerType() || !(*I)->getPointeeType()->isVoidType() ||
282         (*I)->getPointeeType().getQualifiers().getAddressSpace() !=
283             LangAS::opencl_local) {
284       // Get the location of the error. If a block literal has been passed
285       // (BlockExpr) then we can point straight to the offending argument,
286       // else we just point to the variable reference.
287       SourceLocation ErrorLoc;
288       if (isa<BlockExpr>(BlockArg)) {
289         BlockDecl *BD = cast<BlockExpr>(BlockArg)->getBlockDecl();
290         ErrorLoc = BD->getParamDecl(ArgCounter)->getLocStart();
291       } else if (isa<DeclRefExpr>(BlockArg)) {
292         ErrorLoc = cast<DeclRefExpr>(BlockArg)->getLocStart();
293       }
294       S.Diag(ErrorLoc,
295              diag::err_opencl_enqueue_kernel_blocks_non_local_void_args);
296       IllegalParams = true;
297     }
298   }
299 
300   return IllegalParams;
301 }
302 
303 /// OpenCL C v2.0, s6.13.17.6 - Check the argument to the
304 /// get_kernel_work_group_size
305 /// and get_kernel_preferred_work_group_size_multiple builtin functions.
SemaOpenCLBuiltinKernelWorkGroupSize(Sema & S,CallExpr * TheCall)306 static bool SemaOpenCLBuiltinKernelWorkGroupSize(Sema &S, CallExpr *TheCall) {
307   if (checkArgCount(S, TheCall, 1))
308     return true;
309 
310   Expr *BlockArg = TheCall->getArg(0);
311   if (!isBlockPointer(BlockArg)) {
312     S.Diag(BlockArg->getLocStart(),
313            diag::err_opencl_enqueue_kernel_expected_type) << "block";
314     return true;
315   }
316   return checkOpenCLBlockArgs(S, BlockArg);
317 }
318 
319 static bool checkOpenCLEnqueueLocalSizeArgs(Sema &S, CallExpr *TheCall,
320                                             unsigned Start, unsigned End);
321 
322 /// OpenCL v2.0, s6.13.17.1 - Check that sizes are provided for all
323 /// 'local void*' parameter of passed block.
checkOpenCLEnqueueVariadicArgs(Sema & S,CallExpr * TheCall,Expr * BlockArg,unsigned NumNonVarArgs)324 static bool checkOpenCLEnqueueVariadicArgs(Sema &S, CallExpr *TheCall,
325                                            Expr *BlockArg,
326                                            unsigned NumNonVarArgs) {
327   const BlockPointerType *BPT =
328       cast<BlockPointerType>(BlockArg->getType().getCanonicalType());
329   unsigned NumBlockParams =
330       BPT->getPointeeType()->getAs<FunctionProtoType>()->getNumParams();
331   unsigned TotalNumArgs = TheCall->getNumArgs();
332 
333   // For each argument passed to the block, a corresponding uint needs to
334   // be passed to describe the size of the local memory.
335   if (TotalNumArgs != NumBlockParams + NumNonVarArgs) {
336     S.Diag(TheCall->getLocStart(),
337            diag::err_opencl_enqueue_kernel_local_size_args);
338     return true;
339   }
340 
341   // Check that the sizes of the local memory are specified by integers.
342   return checkOpenCLEnqueueLocalSizeArgs(S, TheCall, NumNonVarArgs,
343                                          TotalNumArgs - 1);
344 }
345 
346 /// OpenCL C v2.0, s6.13.17 - Enqueue kernel function contains four different
347 /// overload formats specified in Table 6.13.17.1.
348 /// int enqueue_kernel(queue_t queue,
349 ///                    kernel_enqueue_flags_t flags,
350 ///                    const ndrange_t ndrange,
351 ///                    void (^block)(void))
352 /// int enqueue_kernel(queue_t queue,
353 ///                    kernel_enqueue_flags_t flags,
354 ///                    const ndrange_t ndrange,
355 ///                    uint num_events_in_wait_list,
356 ///                    clk_event_t *event_wait_list,
357 ///                    clk_event_t *event_ret,
358 ///                    void (^block)(void))
359 /// int enqueue_kernel(queue_t queue,
360 ///                    kernel_enqueue_flags_t flags,
361 ///                    const ndrange_t ndrange,
362 ///                    void (^block)(local void*, ...),
363 ///                    uint size0, ...)
364 /// int enqueue_kernel(queue_t queue,
365 ///                    kernel_enqueue_flags_t flags,
366 ///                    const ndrange_t ndrange,
367 ///                    uint num_events_in_wait_list,
368 ///                    clk_event_t *event_wait_list,
369 ///                    clk_event_t *event_ret,
370 ///                    void (^block)(local void*, ...),
371 ///                    uint size0, ...)
SemaOpenCLBuiltinEnqueueKernel(Sema & S,CallExpr * TheCall)372 static bool SemaOpenCLBuiltinEnqueueKernel(Sema &S, CallExpr *TheCall) {
373   unsigned NumArgs = TheCall->getNumArgs();
374 
375   if (NumArgs < 4) {
376     S.Diag(TheCall->getLocStart(), diag::err_typecheck_call_too_few_args);
377     return true;
378   }
379 
380   Expr *Arg0 = TheCall->getArg(0);
381   Expr *Arg1 = TheCall->getArg(1);
382   Expr *Arg2 = TheCall->getArg(2);
383   Expr *Arg3 = TheCall->getArg(3);
384 
385   // First argument always needs to be a queue_t type.
386   if (!Arg0->getType()->isQueueT()) {
387     S.Diag(TheCall->getArg(0)->getLocStart(),
388            diag::err_opencl_enqueue_kernel_expected_type)
389         << S.Context.OCLQueueTy;
390     return true;
391   }
392 
393   // Second argument always needs to be a kernel_enqueue_flags_t enum value.
394   if (!Arg1->getType()->isIntegerType()) {
395     S.Diag(TheCall->getArg(1)->getLocStart(),
396            diag::err_opencl_enqueue_kernel_expected_type)
397         << "'kernel_enqueue_flags_t' (i.e. uint)";
398     return true;
399   }
400 
401   // Third argument is always an ndrange_t type.
402   if (!Arg2->getType()->isNDRangeT()) {
403     S.Diag(TheCall->getArg(2)->getLocStart(),
404            diag::err_opencl_enqueue_kernel_expected_type)
405         << S.Context.OCLNDRangeTy;
406     return true;
407   }
408 
409   // With four arguments, there is only one form that the function could be
410   // called in: no events and no variable arguments.
411   if (NumArgs == 4) {
412     // check that the last argument is the right block type.
413     if (!isBlockPointer(Arg3)) {
414       S.Diag(Arg3->getLocStart(), diag::err_opencl_enqueue_kernel_expected_type)
415           << "block";
416       return true;
417     }
418     // we have a block type, check the prototype
419     const BlockPointerType *BPT =
420         cast<BlockPointerType>(Arg3->getType().getCanonicalType());
421     if (BPT->getPointeeType()->getAs<FunctionProtoType>()->getNumParams() > 0) {
422       S.Diag(Arg3->getLocStart(),
423              diag::err_opencl_enqueue_kernel_blocks_no_args);
424       return true;
425     }
426     return false;
427   }
428   // we can have block + varargs.
429   if (isBlockPointer(Arg3))
430     return (checkOpenCLBlockArgs(S, Arg3) ||
431             checkOpenCLEnqueueVariadicArgs(S, TheCall, Arg3, 4));
432   // last two cases with either exactly 7 args or 7 args and varargs.
433   if (NumArgs >= 7) {
434     // check common block argument.
435     Expr *Arg6 = TheCall->getArg(6);
436     if (!isBlockPointer(Arg6)) {
437       S.Diag(Arg6->getLocStart(), diag::err_opencl_enqueue_kernel_expected_type)
438           << "block";
439       return true;
440     }
441     if (checkOpenCLBlockArgs(S, Arg6))
442       return true;
443 
444     // Forth argument has to be any integer type.
445     if (!Arg3->getType()->isIntegerType()) {
446       S.Diag(TheCall->getArg(3)->getLocStart(),
447              diag::err_opencl_enqueue_kernel_expected_type)
448           << "integer";
449       return true;
450     }
451     // check remaining common arguments.
452     Expr *Arg4 = TheCall->getArg(4);
453     Expr *Arg5 = TheCall->getArg(5);
454 
455     // Fith argument is always passed as pointers to clk_event_t.
456     if (!Arg4->getType()->getPointeeOrArrayElementType()->isClkEventT()) {
457       S.Diag(TheCall->getArg(4)->getLocStart(),
458              diag::err_opencl_enqueue_kernel_expected_type)
459           << S.Context.getPointerType(S.Context.OCLClkEventTy);
460       return true;
461     }
462 
463     // Sixth argument is always passed as pointers to clk_event_t.
464     if (!(Arg5->getType()->isPointerType() &&
465           Arg5->getType()->getPointeeType()->isClkEventT())) {
466       S.Diag(TheCall->getArg(5)->getLocStart(),
467              diag::err_opencl_enqueue_kernel_expected_type)
468           << S.Context.getPointerType(S.Context.OCLClkEventTy);
469       return true;
470     }
471 
472     if (NumArgs == 7)
473       return false;
474 
475     return checkOpenCLEnqueueVariadicArgs(S, TheCall, Arg6, 7);
476   }
477 
478   // None of the specific case has been detected, give generic error
479   S.Diag(TheCall->getLocStart(),
480          diag::err_opencl_enqueue_kernel_incorrect_args);
481   return true;
482 }
483 
484 /// Returns OpenCL access qual.
getOpenCLArgAccess(const Decl * D)485 static OpenCLAccessAttr *getOpenCLArgAccess(const Decl *D) {
486     return D->getAttr<OpenCLAccessAttr>();
487 }
488 
489 /// Returns true if pipe element type is different from the pointer.
checkOpenCLPipeArg(Sema & S,CallExpr * Call)490 static bool checkOpenCLPipeArg(Sema &S, CallExpr *Call) {
491   const Expr *Arg0 = Call->getArg(0);
492   // First argument type should always be pipe.
493   if (!Arg0->getType()->isPipeType()) {
494     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_first_arg)
495         << Call->getDirectCallee() << Arg0->getSourceRange();
496     return true;
497   }
498   OpenCLAccessAttr *AccessQual =
499       getOpenCLArgAccess(cast<DeclRefExpr>(Arg0)->getDecl());
500   // Validates the access qualifier is compatible with the call.
501   // OpenCL v2.0 s6.13.16 - The access qualifiers for pipe should only be
502   // read_only and write_only, and assumed to be read_only if no qualifier is
503   // specified.
504   switch (Call->getDirectCallee()->getBuiltinID()) {
505   case Builtin::BIread_pipe:
506   case Builtin::BIreserve_read_pipe:
507   case Builtin::BIcommit_read_pipe:
508   case Builtin::BIwork_group_reserve_read_pipe:
509   case Builtin::BIsub_group_reserve_read_pipe:
510   case Builtin::BIwork_group_commit_read_pipe:
511   case Builtin::BIsub_group_commit_read_pipe:
512     if (!(!AccessQual || AccessQual->isReadOnly())) {
513       S.Diag(Arg0->getLocStart(),
514              diag::err_opencl_builtin_pipe_invalid_access_modifier)
515           << "read_only" << Arg0->getSourceRange();
516       return true;
517     }
518     break;
519   case Builtin::BIwrite_pipe:
520   case Builtin::BIreserve_write_pipe:
521   case Builtin::BIcommit_write_pipe:
522   case Builtin::BIwork_group_reserve_write_pipe:
523   case Builtin::BIsub_group_reserve_write_pipe:
524   case Builtin::BIwork_group_commit_write_pipe:
525   case Builtin::BIsub_group_commit_write_pipe:
526     if (!(AccessQual && AccessQual->isWriteOnly())) {
527       S.Diag(Arg0->getLocStart(),
528              diag::err_opencl_builtin_pipe_invalid_access_modifier)
529           << "write_only" << Arg0->getSourceRange();
530       return true;
531     }
532     break;
533   default:
534     break;
535   }
536   return false;
537 }
538 
539 /// Returns true if pipe element type is different from the pointer.
checkOpenCLPipePacketType(Sema & S,CallExpr * Call,unsigned Idx)540 static bool checkOpenCLPipePacketType(Sema &S, CallExpr *Call, unsigned Idx) {
541   const Expr *Arg0 = Call->getArg(0);
542   const Expr *ArgIdx = Call->getArg(Idx);
543   const PipeType *PipeTy = cast<PipeType>(Arg0->getType());
544   const QualType EltTy = PipeTy->getElementType();
545   const PointerType *ArgTy = ArgIdx->getType()->getAs<PointerType>();
546   // The Idx argument should be a pointer and the type of the pointer and
547   // the type of pipe element should also be the same.
548   if (!ArgTy ||
549       !S.Context.hasSameType(
550           EltTy, ArgTy->getPointeeType()->getCanonicalTypeInternal())) {
551     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_invalid_arg)
552         << Call->getDirectCallee() << S.Context.getPointerType(EltTy)
553         << ArgIdx->getType() << ArgIdx->getSourceRange();
554     return true;
555   }
556   return false;
557 }
558 
559 // \brief Performs semantic analysis for the read/write_pipe call.
560 // \param S Reference to the semantic analyzer.
561 // \param Call A pointer to the builtin call.
562 // \return True if a semantic error has been found, false otherwise.
SemaBuiltinRWPipe(Sema & S,CallExpr * Call)563 static bool SemaBuiltinRWPipe(Sema &S, CallExpr *Call) {
564   // OpenCL v2.0 s6.13.16.2 - The built-in read/write
565   // functions have two forms.
566   switch (Call->getNumArgs()) {
567   case 2: {
568     if (checkOpenCLPipeArg(S, Call))
569       return true;
570     // The call with 2 arguments should be
571     // read/write_pipe(pipe T, T*).
572     // Check packet type T.
573     if (checkOpenCLPipePacketType(S, Call, 1))
574       return true;
575   } break;
576 
577   case 4: {
578     if (checkOpenCLPipeArg(S, Call))
579       return true;
580     // The call with 4 arguments should be
581     // read/write_pipe(pipe T, reserve_id_t, uint, T*).
582     // Check reserve_id_t.
583     if (!Call->getArg(1)->getType()->isReserveIDT()) {
584       S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_invalid_arg)
585           << Call->getDirectCallee() << S.Context.OCLReserveIDTy
586           << Call->getArg(1)->getType() << Call->getArg(1)->getSourceRange();
587       return true;
588     }
589 
590     // Check the index.
591     const Expr *Arg2 = Call->getArg(2);
592     if (!Arg2->getType()->isIntegerType() &&
593         !Arg2->getType()->isUnsignedIntegerType()) {
594       S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_invalid_arg)
595           << Call->getDirectCallee() << S.Context.UnsignedIntTy
596           << Arg2->getType() << Arg2->getSourceRange();
597       return true;
598     }
599 
600     // Check packet type T.
601     if (checkOpenCLPipePacketType(S, Call, 3))
602       return true;
603   } break;
604   default:
605     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_arg_num)
606         << Call->getDirectCallee() << Call->getSourceRange();
607     return true;
608   }
609 
610   return false;
611 }
612 
613 // \brief Performs a semantic analysis on the {work_group_/sub_group_
614 //        /_}reserve_{read/write}_pipe
615 // \param S Reference to the semantic analyzer.
616 // \param Call The call to the builtin function to be analyzed.
617 // \return True if a semantic error was found, false otherwise.
SemaBuiltinReserveRWPipe(Sema & S,CallExpr * Call)618 static bool SemaBuiltinReserveRWPipe(Sema &S, CallExpr *Call) {
619   if (checkArgCount(S, Call, 2))
620     return true;
621 
622   if (checkOpenCLPipeArg(S, Call))
623     return true;
624 
625   // Check the reserve size.
626   if (!Call->getArg(1)->getType()->isIntegerType() &&
627       !Call->getArg(1)->getType()->isUnsignedIntegerType()) {
628     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_invalid_arg)
629         << Call->getDirectCallee() << S.Context.UnsignedIntTy
630         << Call->getArg(1)->getType() << Call->getArg(1)->getSourceRange();
631     return true;
632   }
633 
634   return false;
635 }
636 
637 // \brief Performs a semantic analysis on {work_group_/sub_group_
638 //        /_}commit_{read/write}_pipe
639 // \param S Reference to the semantic analyzer.
640 // \param Call The call to the builtin function to be analyzed.
641 // \return True if a semantic error was found, false otherwise.
SemaBuiltinCommitRWPipe(Sema & S,CallExpr * Call)642 static bool SemaBuiltinCommitRWPipe(Sema &S, CallExpr *Call) {
643   if (checkArgCount(S, Call, 2))
644     return true;
645 
646   if (checkOpenCLPipeArg(S, Call))
647     return true;
648 
649   // Check reserve_id_t.
650   if (!Call->getArg(1)->getType()->isReserveIDT()) {
651     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_invalid_arg)
652         << Call->getDirectCallee() << S.Context.OCLReserveIDTy
653         << Call->getArg(1)->getType() << Call->getArg(1)->getSourceRange();
654     return true;
655   }
656 
657   return false;
658 }
659 
660 // \brief Performs a semantic analysis on the call to built-in Pipe
661 //        Query Functions.
662 // \param S Reference to the semantic analyzer.
663 // \param Call The call to the builtin function to be analyzed.
664 // \return True if a semantic error was found, false otherwise.
SemaBuiltinPipePackets(Sema & S,CallExpr * Call)665 static bool SemaBuiltinPipePackets(Sema &S, CallExpr *Call) {
666   if (checkArgCount(S, Call, 1))
667     return true;
668 
669   if (!Call->getArg(0)->getType()->isPipeType()) {
670     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_pipe_first_arg)
671         << Call->getDirectCallee() << Call->getArg(0)->getSourceRange();
672     return true;
673   }
674 
675   return false;
676 }
677 // \brief OpenCL v2.0 s6.13.9 - Address space qualifier functions.
678 // \brief Performs semantic analysis for the to_global/local/private call.
679 // \param S Reference to the semantic analyzer.
680 // \param BuiltinID ID of the builtin function.
681 // \param Call A pointer to the builtin call.
682 // \return True if a semantic error has been found, false otherwise.
SemaOpenCLBuiltinToAddr(Sema & S,unsigned BuiltinID,CallExpr * Call)683 static bool SemaOpenCLBuiltinToAddr(Sema &S, unsigned BuiltinID,
684                                     CallExpr *Call) {
685   if (Call->getNumArgs() != 1) {
686     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_to_addr_arg_num)
687         << Call->getDirectCallee() << Call->getSourceRange();
688     return true;
689   }
690 
691   auto RT = Call->getArg(0)->getType();
692   if (!RT->isPointerType() || RT->getPointeeType()
693       .getAddressSpace() == LangAS::opencl_constant) {
694     S.Diag(Call->getLocStart(), diag::err_opencl_builtin_to_addr_invalid_arg)
695         << Call->getArg(0) << Call->getDirectCallee() << Call->getSourceRange();
696     return true;
697   }
698 
699   RT = RT->getPointeeType();
700   auto Qual = RT.getQualifiers();
701   switch (BuiltinID) {
702   case Builtin::BIto_global:
703     Qual.setAddressSpace(LangAS::opencl_global);
704     break;
705   case Builtin::BIto_local:
706     Qual.setAddressSpace(LangAS::opencl_local);
707     break;
708   default:
709     Qual.removeAddressSpace();
710   }
711   Call->setType(S.Context.getPointerType(S.Context.getQualifiedType(
712       RT.getUnqualifiedType(), Qual)));
713 
714   return false;
715 }
716 
717 ExprResult
CheckBuiltinFunctionCall(FunctionDecl * FDecl,unsigned BuiltinID,CallExpr * TheCall)718 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
719                                CallExpr *TheCall) {
720   ExprResult TheCallResult(TheCall);
721 
722   // Find out if any arguments are required to be integer constant expressions.
723   unsigned ICEArguments = 0;
724   ASTContext::GetBuiltinTypeError Error;
725   Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
726   if (Error != ASTContext::GE_None)
727     ICEArguments = 0;  // Don't diagnose previously diagnosed errors.
728 
729   // If any arguments are required to be ICE's, check and diagnose.
730   for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
731     // Skip arguments not required to be ICE's.
732     if ((ICEArguments & (1 << ArgNo)) == 0) continue;
733 
734     llvm::APSInt Result;
735     if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
736       return true;
737     ICEArguments &= ~(1 << ArgNo);
738   }
739 
740   switch (BuiltinID) {
741   case Builtin::BI__builtin___CFStringMakeConstantString:
742     assert(TheCall->getNumArgs() == 1 &&
743            "Wrong # arguments to builtin CFStringMakeConstantString");
744     if (CheckObjCString(TheCall->getArg(0)))
745       return ExprError();
746     break;
747   case Builtin::BI__builtin_stdarg_start:
748   case Builtin::BI__builtin_va_start:
749     if (SemaBuiltinVAStart(TheCall))
750       return ExprError();
751     break;
752   case Builtin::BI__va_start: {
753     switch (Context.getTargetInfo().getTriple().getArch()) {
754     case llvm::Triple::arm:
755     case llvm::Triple::thumb:
756       if (SemaBuiltinVAStartARM(TheCall))
757         return ExprError();
758       break;
759     default:
760       if (SemaBuiltinVAStart(TheCall))
761         return ExprError();
762       break;
763     }
764     break;
765   }
766   case Builtin::BI__builtin_isgreater:
767   case Builtin::BI__builtin_isgreaterequal:
768   case Builtin::BI__builtin_isless:
769   case Builtin::BI__builtin_islessequal:
770   case Builtin::BI__builtin_islessgreater:
771   case Builtin::BI__builtin_isunordered:
772     if (SemaBuiltinUnorderedCompare(TheCall))
773       return ExprError();
774     break;
775   case Builtin::BI__builtin_fpclassify:
776     if (SemaBuiltinFPClassification(TheCall, 6))
777       return ExprError();
778     break;
779   case Builtin::BI__builtin_isfinite:
780   case Builtin::BI__builtin_isinf:
781   case Builtin::BI__builtin_isinf_sign:
782   case Builtin::BI__builtin_isnan:
783   case Builtin::BI__builtin_isnormal:
784     if (SemaBuiltinFPClassification(TheCall, 1))
785       return ExprError();
786     break;
787   case Builtin::BI__builtin_shufflevector:
788     return SemaBuiltinShuffleVector(TheCall);
789     // TheCall will be freed by the smart pointer here, but that's fine, since
790     // SemaBuiltinShuffleVector guts it, but then doesn't release it.
791   case Builtin::BI__builtin_prefetch:
792     if (SemaBuiltinPrefetch(TheCall))
793       return ExprError();
794     break;
795   case Builtin::BI__assume:
796   case Builtin::BI__builtin_assume:
797     if (SemaBuiltinAssume(TheCall))
798       return ExprError();
799     break;
800   case Builtin::BI__builtin_assume_aligned:
801     if (SemaBuiltinAssumeAligned(TheCall))
802       return ExprError();
803     break;
804   case Builtin::BI__builtin_object_size:
805     if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3))
806       return ExprError();
807     break;
808   case Builtin::BI__builtin_longjmp:
809     if (SemaBuiltinLongjmp(TheCall))
810       return ExprError();
811     break;
812   case Builtin::BI__builtin_setjmp:
813     if (SemaBuiltinSetjmp(TheCall))
814       return ExprError();
815     break;
816   case Builtin::BI_setjmp:
817   case Builtin::BI_setjmpex:
818     if (checkArgCount(*this, TheCall, 1))
819       return true;
820     break;
821 
822   case Builtin::BI__builtin_classify_type:
823     if (checkArgCount(*this, TheCall, 1)) return true;
824     TheCall->setType(Context.IntTy);
825     break;
826   case Builtin::BI__builtin_constant_p:
827     if (checkArgCount(*this, TheCall, 1)) return true;
828     TheCall->setType(Context.IntTy);
829     break;
830   case Builtin::BI__sync_fetch_and_add:
831   case Builtin::BI__sync_fetch_and_add_1:
832   case Builtin::BI__sync_fetch_and_add_2:
833   case Builtin::BI__sync_fetch_and_add_4:
834   case Builtin::BI__sync_fetch_and_add_8:
835   case Builtin::BI__sync_fetch_and_add_16:
836   case Builtin::BI__sync_fetch_and_sub:
837   case Builtin::BI__sync_fetch_and_sub_1:
838   case Builtin::BI__sync_fetch_and_sub_2:
839   case Builtin::BI__sync_fetch_and_sub_4:
840   case Builtin::BI__sync_fetch_and_sub_8:
841   case Builtin::BI__sync_fetch_and_sub_16:
842   case Builtin::BI__sync_fetch_and_or:
843   case Builtin::BI__sync_fetch_and_or_1:
844   case Builtin::BI__sync_fetch_and_or_2:
845   case Builtin::BI__sync_fetch_and_or_4:
846   case Builtin::BI__sync_fetch_and_or_8:
847   case Builtin::BI__sync_fetch_and_or_16:
848   case Builtin::BI__sync_fetch_and_and:
849   case Builtin::BI__sync_fetch_and_and_1:
850   case Builtin::BI__sync_fetch_and_and_2:
851   case Builtin::BI__sync_fetch_and_and_4:
852   case Builtin::BI__sync_fetch_and_and_8:
853   case Builtin::BI__sync_fetch_and_and_16:
854   case Builtin::BI__sync_fetch_and_xor:
855   case Builtin::BI__sync_fetch_and_xor_1:
856   case Builtin::BI__sync_fetch_and_xor_2:
857   case Builtin::BI__sync_fetch_and_xor_4:
858   case Builtin::BI__sync_fetch_and_xor_8:
859   case Builtin::BI__sync_fetch_and_xor_16:
860   case Builtin::BI__sync_fetch_and_nand:
861   case Builtin::BI__sync_fetch_and_nand_1:
862   case Builtin::BI__sync_fetch_and_nand_2:
863   case Builtin::BI__sync_fetch_and_nand_4:
864   case Builtin::BI__sync_fetch_and_nand_8:
865   case Builtin::BI__sync_fetch_and_nand_16:
866   case Builtin::BI__sync_add_and_fetch:
867   case Builtin::BI__sync_add_and_fetch_1:
868   case Builtin::BI__sync_add_and_fetch_2:
869   case Builtin::BI__sync_add_and_fetch_4:
870   case Builtin::BI__sync_add_and_fetch_8:
871   case Builtin::BI__sync_add_and_fetch_16:
872   case Builtin::BI__sync_sub_and_fetch:
873   case Builtin::BI__sync_sub_and_fetch_1:
874   case Builtin::BI__sync_sub_and_fetch_2:
875   case Builtin::BI__sync_sub_and_fetch_4:
876   case Builtin::BI__sync_sub_and_fetch_8:
877   case Builtin::BI__sync_sub_and_fetch_16:
878   case Builtin::BI__sync_and_and_fetch:
879   case Builtin::BI__sync_and_and_fetch_1:
880   case Builtin::BI__sync_and_and_fetch_2:
881   case Builtin::BI__sync_and_and_fetch_4:
882   case Builtin::BI__sync_and_and_fetch_8:
883   case Builtin::BI__sync_and_and_fetch_16:
884   case Builtin::BI__sync_or_and_fetch:
885   case Builtin::BI__sync_or_and_fetch_1:
886   case Builtin::BI__sync_or_and_fetch_2:
887   case Builtin::BI__sync_or_and_fetch_4:
888   case Builtin::BI__sync_or_and_fetch_8:
889   case Builtin::BI__sync_or_and_fetch_16:
890   case Builtin::BI__sync_xor_and_fetch:
891   case Builtin::BI__sync_xor_and_fetch_1:
892   case Builtin::BI__sync_xor_and_fetch_2:
893   case Builtin::BI__sync_xor_and_fetch_4:
894   case Builtin::BI__sync_xor_and_fetch_8:
895   case Builtin::BI__sync_xor_and_fetch_16:
896   case Builtin::BI__sync_nand_and_fetch:
897   case Builtin::BI__sync_nand_and_fetch_1:
898   case Builtin::BI__sync_nand_and_fetch_2:
899   case Builtin::BI__sync_nand_and_fetch_4:
900   case Builtin::BI__sync_nand_and_fetch_8:
901   case Builtin::BI__sync_nand_and_fetch_16:
902   case Builtin::BI__sync_val_compare_and_swap:
903   case Builtin::BI__sync_val_compare_and_swap_1:
904   case Builtin::BI__sync_val_compare_and_swap_2:
905   case Builtin::BI__sync_val_compare_and_swap_4:
906   case Builtin::BI__sync_val_compare_and_swap_8:
907   case Builtin::BI__sync_val_compare_and_swap_16:
908   case Builtin::BI__sync_bool_compare_and_swap:
909   case Builtin::BI__sync_bool_compare_and_swap_1:
910   case Builtin::BI__sync_bool_compare_and_swap_2:
911   case Builtin::BI__sync_bool_compare_and_swap_4:
912   case Builtin::BI__sync_bool_compare_and_swap_8:
913   case Builtin::BI__sync_bool_compare_and_swap_16:
914   case Builtin::BI__sync_lock_test_and_set:
915   case Builtin::BI__sync_lock_test_and_set_1:
916   case Builtin::BI__sync_lock_test_and_set_2:
917   case Builtin::BI__sync_lock_test_and_set_4:
918   case Builtin::BI__sync_lock_test_and_set_8:
919   case Builtin::BI__sync_lock_test_and_set_16:
920   case Builtin::BI__sync_lock_release:
921   case Builtin::BI__sync_lock_release_1:
922   case Builtin::BI__sync_lock_release_2:
923   case Builtin::BI__sync_lock_release_4:
924   case Builtin::BI__sync_lock_release_8:
925   case Builtin::BI__sync_lock_release_16:
926   case Builtin::BI__sync_swap:
927   case Builtin::BI__sync_swap_1:
928   case Builtin::BI__sync_swap_2:
929   case Builtin::BI__sync_swap_4:
930   case Builtin::BI__sync_swap_8:
931   case Builtin::BI__sync_swap_16:
932     return SemaBuiltinAtomicOverloaded(TheCallResult);
933   case Builtin::BI__builtin_nontemporal_load:
934   case Builtin::BI__builtin_nontemporal_store:
935     return SemaBuiltinNontemporalOverloaded(TheCallResult);
936 #define BUILTIN(ID, TYPE, ATTRS)
937 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
938   case Builtin::BI##ID: \
939     return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID);
940 #include "clang/Basic/Builtins.def"
941   case Builtin::BI__builtin_annotation:
942     if (SemaBuiltinAnnotation(*this, TheCall))
943       return ExprError();
944     break;
945   case Builtin::BI__builtin_addressof:
946     if (SemaBuiltinAddressof(*this, TheCall))
947       return ExprError();
948     break;
949   case Builtin::BI__builtin_add_overflow:
950   case Builtin::BI__builtin_sub_overflow:
951   case Builtin::BI__builtin_mul_overflow:
952     if (SemaBuiltinOverflow(*this, TheCall))
953       return ExprError();
954     break;
955   case Builtin::BI__builtin_operator_new:
956   case Builtin::BI__builtin_operator_delete:
957     if (!getLangOpts().CPlusPlus) {
958       Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language)
959         << (BuiltinID == Builtin::BI__builtin_operator_new
960                 ? "__builtin_operator_new"
961                 : "__builtin_operator_delete")
962         << "C++";
963       return ExprError();
964     }
965     // CodeGen assumes it can find the global new and delete to call,
966     // so ensure that they are declared.
967     DeclareGlobalNewDelete();
968     break;
969 
970   // check secure string manipulation functions where overflows
971   // are detectable at compile time
972   case Builtin::BI__builtin___memcpy_chk:
973   case Builtin::BI__builtin___memmove_chk:
974   case Builtin::BI__builtin___memset_chk:
975   case Builtin::BI__builtin___strlcat_chk:
976   case Builtin::BI__builtin___strlcpy_chk:
977   case Builtin::BI__builtin___strncat_chk:
978   case Builtin::BI__builtin___strncpy_chk:
979   case Builtin::BI__builtin___stpncpy_chk:
980     SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3);
981     break;
982   case Builtin::BI__builtin___memccpy_chk:
983     SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4);
984     break;
985   case Builtin::BI__builtin___snprintf_chk:
986   case Builtin::BI__builtin___vsnprintf_chk:
987     SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3);
988     break;
989   case Builtin::BI__builtin_call_with_static_chain:
990     if (SemaBuiltinCallWithStaticChain(*this, TheCall))
991       return ExprError();
992     break;
993   case Builtin::BI__exception_code:
994   case Builtin::BI_exception_code:
995     if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHExceptScope,
996                                  diag::err_seh___except_block))
997       return ExprError();
998     break;
999   case Builtin::BI__exception_info:
1000   case Builtin::BI_exception_info:
1001     if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHFilterScope,
1002                                  diag::err_seh___except_filter))
1003       return ExprError();
1004     break;
1005   case Builtin::BI__GetExceptionInfo:
1006     if (checkArgCount(*this, TheCall, 1))
1007       return ExprError();
1008 
1009     if (CheckCXXThrowOperand(
1010             TheCall->getLocStart(),
1011             Context.getExceptionObjectType(FDecl->getParamDecl(0)->getType()),
1012             TheCall))
1013       return ExprError();
1014 
1015     TheCall->setType(Context.VoidPtrTy);
1016     break;
1017   // OpenCL v2.0, s6.13.16 - Pipe functions
1018   case Builtin::BIread_pipe:
1019   case Builtin::BIwrite_pipe:
1020     // Since those two functions are declared with var args, we need a semantic
1021     // check for the argument.
1022     if (SemaBuiltinRWPipe(*this, TheCall))
1023       return ExprError();
1024     break;
1025   case Builtin::BIreserve_read_pipe:
1026   case Builtin::BIreserve_write_pipe:
1027   case Builtin::BIwork_group_reserve_read_pipe:
1028   case Builtin::BIwork_group_reserve_write_pipe:
1029   case Builtin::BIsub_group_reserve_read_pipe:
1030   case Builtin::BIsub_group_reserve_write_pipe:
1031     if (SemaBuiltinReserveRWPipe(*this, TheCall))
1032       return ExprError();
1033     // Since return type of reserve_read/write_pipe built-in function is
1034     // reserve_id_t, which is not defined in the builtin def file , we used int
1035     // as return type and need to override the return type of these functions.
1036     TheCall->setType(Context.OCLReserveIDTy);
1037     break;
1038   case Builtin::BIcommit_read_pipe:
1039   case Builtin::BIcommit_write_pipe:
1040   case Builtin::BIwork_group_commit_read_pipe:
1041   case Builtin::BIwork_group_commit_write_pipe:
1042   case Builtin::BIsub_group_commit_read_pipe:
1043   case Builtin::BIsub_group_commit_write_pipe:
1044     if (SemaBuiltinCommitRWPipe(*this, TheCall))
1045       return ExprError();
1046     break;
1047   case Builtin::BIget_pipe_num_packets:
1048   case Builtin::BIget_pipe_max_packets:
1049     if (SemaBuiltinPipePackets(*this, TheCall))
1050       return ExprError();
1051     break;
1052   case Builtin::BIto_global:
1053   case Builtin::BIto_local:
1054   case Builtin::BIto_private:
1055     if (SemaOpenCLBuiltinToAddr(*this, BuiltinID, TheCall))
1056       return ExprError();
1057     break;
1058   // OpenCL v2.0, s6.13.17 - Enqueue kernel functions.
1059   case Builtin::BIenqueue_kernel:
1060     if (SemaOpenCLBuiltinEnqueueKernel(*this, TheCall))
1061       return ExprError();
1062     break;
1063   case Builtin::BIget_kernel_work_group_size:
1064   case Builtin::BIget_kernel_preferred_work_group_size_multiple:
1065     if (SemaOpenCLBuiltinKernelWorkGroupSize(*this, TheCall))
1066       return ExprError();
1067   }
1068 
1069   // Since the target specific builtins for each arch overlap, only check those
1070   // of the arch we are compiling for.
1071   if (Context.BuiltinInfo.isTSBuiltin(BuiltinID)) {
1072     switch (Context.getTargetInfo().getTriple().getArch()) {
1073       case llvm::Triple::arm:
1074       case llvm::Triple::armeb:
1075       case llvm::Triple::thumb:
1076       case llvm::Triple::thumbeb:
1077         if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
1078           return ExprError();
1079         break;
1080       case llvm::Triple::aarch64:
1081       case llvm::Triple::aarch64_be:
1082         if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall))
1083           return ExprError();
1084         break;
1085       case llvm::Triple::mips:
1086       case llvm::Triple::mipsel:
1087       case llvm::Triple::mips64:
1088       case llvm::Triple::mips64el:
1089         if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall))
1090           return ExprError();
1091         break;
1092       case llvm::Triple::systemz:
1093         if (CheckSystemZBuiltinFunctionCall(BuiltinID, TheCall))
1094           return ExprError();
1095         break;
1096       case llvm::Triple::x86:
1097       case llvm::Triple::x86_64:
1098         if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall))
1099           return ExprError();
1100         break;
1101       case llvm::Triple::ppc:
1102       case llvm::Triple::ppc64:
1103       case llvm::Triple::ppc64le:
1104         if (CheckPPCBuiltinFunctionCall(BuiltinID, TheCall))
1105           return ExprError();
1106         break;
1107       default:
1108         break;
1109     }
1110   }
1111 
1112   return TheCallResult;
1113 }
1114 
1115 // Get the valid immediate range for the specified NEON type code.
RFT(unsigned t,bool shift=false,bool ForceQuad=false)1116 static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) {
1117   NeonTypeFlags Type(t);
1118   int IsQuad = ForceQuad ? true : Type.isQuad();
1119   switch (Type.getEltType()) {
1120   case NeonTypeFlags::Int8:
1121   case NeonTypeFlags::Poly8:
1122     return shift ? 7 : (8 << IsQuad) - 1;
1123   case NeonTypeFlags::Int16:
1124   case NeonTypeFlags::Poly16:
1125     return shift ? 15 : (4 << IsQuad) - 1;
1126   case NeonTypeFlags::Int32:
1127     return shift ? 31 : (2 << IsQuad) - 1;
1128   case NeonTypeFlags::Int64:
1129   case NeonTypeFlags::Poly64:
1130     return shift ? 63 : (1 << IsQuad) - 1;
1131   case NeonTypeFlags::Poly128:
1132     return shift ? 127 : (1 << IsQuad) - 1;
1133   case NeonTypeFlags::Float16:
1134     assert(!shift && "cannot shift float types!");
1135     return (4 << IsQuad) - 1;
1136   case NeonTypeFlags::Float32:
1137     assert(!shift && "cannot shift float types!");
1138     return (2 << IsQuad) - 1;
1139   case NeonTypeFlags::Float64:
1140     assert(!shift && "cannot shift float types!");
1141     return (1 << IsQuad) - 1;
1142   }
1143   llvm_unreachable("Invalid NeonTypeFlag!");
1144 }
1145 
1146 /// getNeonEltType - Return the QualType corresponding to the elements of
1147 /// the vector type specified by the NeonTypeFlags.  This is used to check
1148 /// the pointer arguments for Neon load/store intrinsics.
getNeonEltType(NeonTypeFlags Flags,ASTContext & Context,bool IsPolyUnsigned,bool IsInt64Long)1149 static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context,
1150                                bool IsPolyUnsigned, bool IsInt64Long) {
1151   switch (Flags.getEltType()) {
1152   case NeonTypeFlags::Int8:
1153     return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
1154   case NeonTypeFlags::Int16:
1155     return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
1156   case NeonTypeFlags::Int32:
1157     return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
1158   case NeonTypeFlags::Int64:
1159     if (IsInt64Long)
1160       return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy;
1161     else
1162       return Flags.isUnsigned() ? Context.UnsignedLongLongTy
1163                                 : Context.LongLongTy;
1164   case NeonTypeFlags::Poly8:
1165     return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy;
1166   case NeonTypeFlags::Poly16:
1167     return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy;
1168   case NeonTypeFlags::Poly64:
1169     if (IsInt64Long)
1170       return Context.UnsignedLongTy;
1171     else
1172       return Context.UnsignedLongLongTy;
1173   case NeonTypeFlags::Poly128:
1174     break;
1175   case NeonTypeFlags::Float16:
1176     return Context.HalfTy;
1177   case NeonTypeFlags::Float32:
1178     return Context.FloatTy;
1179   case NeonTypeFlags::Float64:
1180     return Context.DoubleTy;
1181   }
1182   llvm_unreachable("Invalid NeonTypeFlag!");
1183 }
1184 
CheckNeonBuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1185 bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1186   llvm::APSInt Result;
1187   uint64_t mask = 0;
1188   unsigned TV = 0;
1189   int PtrArgNum = -1;
1190   bool HasConstPtr = false;
1191   switch (BuiltinID) {
1192 #define GET_NEON_OVERLOAD_CHECK
1193 #include "clang/Basic/arm_neon.inc"
1194 #undef GET_NEON_OVERLOAD_CHECK
1195   }
1196 
1197   // For NEON intrinsics which are overloaded on vector element type, validate
1198   // the immediate which specifies which variant to emit.
1199   unsigned ImmArg = TheCall->getNumArgs()-1;
1200   if (mask) {
1201     if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
1202       return true;
1203 
1204     TV = Result.getLimitedValue(64);
1205     if ((TV > 63) || (mask & (1ULL << TV)) == 0)
1206       return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
1207         << TheCall->getArg(ImmArg)->getSourceRange();
1208   }
1209 
1210   if (PtrArgNum >= 0) {
1211     // Check that pointer arguments have the specified type.
1212     Expr *Arg = TheCall->getArg(PtrArgNum);
1213     if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
1214       Arg = ICE->getSubExpr();
1215     ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
1216     QualType RHSTy = RHS.get()->getType();
1217 
1218     llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
1219     bool IsPolyUnsigned = Arch == llvm::Triple::aarch64;
1220     bool IsInt64Long =
1221         Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong;
1222     QualType EltTy =
1223         getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long);
1224     if (HasConstPtr)
1225       EltTy = EltTy.withConst();
1226     QualType LHSTy = Context.getPointerType(EltTy);
1227     AssignConvertType ConvTy;
1228     ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
1229     if (RHS.isInvalid())
1230       return true;
1231     if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
1232                                  RHS.get(), AA_Assigning))
1233       return true;
1234   }
1235 
1236   // For NEON intrinsics which take an immediate value as part of the
1237   // instruction, range check them here.
1238   unsigned i = 0, l = 0, u = 0;
1239   switch (BuiltinID) {
1240   default:
1241     return false;
1242 #define GET_NEON_IMMEDIATE_CHECK
1243 #include "clang/Basic/arm_neon.inc"
1244 #undef GET_NEON_IMMEDIATE_CHECK
1245   }
1246 
1247   return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
1248 }
1249 
CheckARMBuiltinExclusiveCall(unsigned BuiltinID,CallExpr * TheCall,unsigned MaxWidth)1250 bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
1251                                         unsigned MaxWidth) {
1252   assert((BuiltinID == ARM::BI__builtin_arm_ldrex ||
1253           BuiltinID == ARM::BI__builtin_arm_ldaex ||
1254           BuiltinID == ARM::BI__builtin_arm_strex ||
1255           BuiltinID == ARM::BI__builtin_arm_stlex ||
1256           BuiltinID == AArch64::BI__builtin_arm_ldrex ||
1257           BuiltinID == AArch64::BI__builtin_arm_ldaex ||
1258           BuiltinID == AArch64::BI__builtin_arm_strex ||
1259           BuiltinID == AArch64::BI__builtin_arm_stlex) &&
1260          "unexpected ARM builtin");
1261   bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex ||
1262                  BuiltinID == ARM::BI__builtin_arm_ldaex ||
1263                  BuiltinID == AArch64::BI__builtin_arm_ldrex ||
1264                  BuiltinID == AArch64::BI__builtin_arm_ldaex;
1265 
1266   DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1267 
1268   // Ensure that we have the proper number of arguments.
1269   if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2))
1270     return true;
1271 
1272   // Inspect the pointer argument of the atomic builtin.  This should always be
1273   // a pointer type, whose element is an integral scalar or pointer type.
1274   // Because it is a pointer type, we don't have to worry about any implicit
1275   // casts here.
1276   Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1);
1277   ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg);
1278   if (PointerArgRes.isInvalid())
1279     return true;
1280   PointerArg = PointerArgRes.get();
1281 
1282   const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>();
1283   if (!pointerType) {
1284     Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
1285       << PointerArg->getType() << PointerArg->getSourceRange();
1286     return true;
1287   }
1288 
1289   // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next
1290   // task is to insert the appropriate casts into the AST. First work out just
1291   // what the appropriate type is.
1292   QualType ValType = pointerType->getPointeeType();
1293   QualType AddrType = ValType.getUnqualifiedType().withVolatile();
1294   if (IsLdrex)
1295     AddrType.addConst();
1296 
1297   // Issue a warning if the cast is dodgy.
1298   CastKind CastNeeded = CK_NoOp;
1299   if (!AddrType.isAtLeastAsQualifiedAs(ValType)) {
1300     CastNeeded = CK_BitCast;
1301     Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers)
1302       << PointerArg->getType()
1303       << Context.getPointerType(AddrType)
1304       << AA_Passing << PointerArg->getSourceRange();
1305   }
1306 
1307   // Finally, do the cast and replace the argument with the corrected version.
1308   AddrType = Context.getPointerType(AddrType);
1309   PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded);
1310   if (PointerArgRes.isInvalid())
1311     return true;
1312   PointerArg = PointerArgRes.get();
1313 
1314   TheCall->setArg(IsLdrex ? 0 : 1, PointerArg);
1315 
1316   // In general, we allow ints, floats and pointers to be loaded and stored.
1317   if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
1318       !ValType->isBlockPointerType() && !ValType->isFloatingType()) {
1319     Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr)
1320       << PointerArg->getType() << PointerArg->getSourceRange();
1321     return true;
1322   }
1323 
1324   // But ARM doesn't have instructions to deal with 128-bit versions.
1325   if (Context.getTypeSize(ValType) > MaxWidth) {
1326     assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate");
1327     Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size)
1328       << PointerArg->getType() << PointerArg->getSourceRange();
1329     return true;
1330   }
1331 
1332   switch (ValType.getObjCLifetime()) {
1333   case Qualifiers::OCL_None:
1334   case Qualifiers::OCL_ExplicitNone:
1335     // okay
1336     break;
1337 
1338   case Qualifiers::OCL_Weak:
1339   case Qualifiers::OCL_Strong:
1340   case Qualifiers::OCL_Autoreleasing:
1341     Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
1342       << ValType << PointerArg->getSourceRange();
1343     return true;
1344   }
1345 
1346   if (IsLdrex) {
1347     TheCall->setType(ValType);
1348     return false;
1349   }
1350 
1351   // Initialize the argument to be stored.
1352   ExprResult ValArg = TheCall->getArg(0);
1353   InitializedEntity Entity = InitializedEntity::InitializeParameter(
1354       Context, ValType, /*consume*/ false);
1355   ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg);
1356   if (ValArg.isInvalid())
1357     return true;
1358   TheCall->setArg(0, ValArg.get());
1359 
1360   // __builtin_arm_strex always returns an int. It's marked as such in the .def,
1361   // but the custom checker bypasses all default analysis.
1362   TheCall->setType(Context.IntTy);
1363   return false;
1364 }
1365 
CheckARMBuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1366 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1367   llvm::APSInt Result;
1368 
1369   if (BuiltinID == ARM::BI__builtin_arm_ldrex ||
1370       BuiltinID == ARM::BI__builtin_arm_ldaex ||
1371       BuiltinID == ARM::BI__builtin_arm_strex ||
1372       BuiltinID == ARM::BI__builtin_arm_stlex) {
1373     return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64);
1374   }
1375 
1376   if (BuiltinID == ARM::BI__builtin_arm_prefetch) {
1377     return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
1378       SemaBuiltinConstantArgRange(TheCall, 2, 0, 1);
1379   }
1380 
1381   if (BuiltinID == ARM::BI__builtin_arm_rsr64 ||
1382       BuiltinID == ARM::BI__builtin_arm_wsr64)
1383     return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 3, false);
1384 
1385   if (BuiltinID == ARM::BI__builtin_arm_rsr ||
1386       BuiltinID == ARM::BI__builtin_arm_rsrp ||
1387       BuiltinID == ARM::BI__builtin_arm_wsr ||
1388       BuiltinID == ARM::BI__builtin_arm_wsrp)
1389     return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
1390 
1391   if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
1392     return true;
1393 
1394   // For intrinsics which take an immediate value as part of the instruction,
1395   // range check them here.
1396   unsigned i = 0, l = 0, u = 0;
1397   switch (BuiltinID) {
1398   default: return false;
1399   case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
1400   case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
1401   case ARM::BI__builtin_arm_vcvtr_f:
1402   case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
1403   case ARM::BI__builtin_arm_dmb:
1404   case ARM::BI__builtin_arm_dsb:
1405   case ARM::BI__builtin_arm_isb:
1406   case ARM::BI__builtin_arm_dbg: l = 0; u = 15; break;
1407   }
1408 
1409   // FIXME: VFP Intrinsics should error if VFP not present.
1410   return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
1411 }
1412 
CheckAArch64BuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1413 bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID,
1414                                          CallExpr *TheCall) {
1415   llvm::APSInt Result;
1416 
1417   if (BuiltinID == AArch64::BI__builtin_arm_ldrex ||
1418       BuiltinID == AArch64::BI__builtin_arm_ldaex ||
1419       BuiltinID == AArch64::BI__builtin_arm_strex ||
1420       BuiltinID == AArch64::BI__builtin_arm_stlex) {
1421     return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128);
1422   }
1423 
1424   if (BuiltinID == AArch64::BI__builtin_arm_prefetch) {
1425     return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
1426       SemaBuiltinConstantArgRange(TheCall, 2, 0, 2) ||
1427       SemaBuiltinConstantArgRange(TheCall, 3, 0, 1) ||
1428       SemaBuiltinConstantArgRange(TheCall, 4, 0, 1);
1429   }
1430 
1431   if (BuiltinID == AArch64::BI__builtin_arm_rsr64 ||
1432       BuiltinID == AArch64::BI__builtin_arm_wsr64)
1433     return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
1434 
1435   if (BuiltinID == AArch64::BI__builtin_arm_rsr ||
1436       BuiltinID == AArch64::BI__builtin_arm_rsrp ||
1437       BuiltinID == AArch64::BI__builtin_arm_wsr ||
1438       BuiltinID == AArch64::BI__builtin_arm_wsrp)
1439     return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
1440 
1441   if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
1442     return true;
1443 
1444   // For intrinsics which take an immediate value as part of the instruction,
1445   // range check them here.
1446   unsigned i = 0, l = 0, u = 0;
1447   switch (BuiltinID) {
1448   default: return false;
1449   case AArch64::BI__builtin_arm_dmb:
1450   case AArch64::BI__builtin_arm_dsb:
1451   case AArch64::BI__builtin_arm_isb: l = 0; u = 15; break;
1452   }
1453 
1454   return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
1455 }
1456 
CheckMipsBuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1457 bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1458   unsigned i = 0, l = 0, u = 0;
1459   switch (BuiltinID) {
1460   default: return false;
1461   case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break;
1462   case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break;
1463   case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break;
1464   case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break;
1465   case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break;
1466   case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break;
1467   case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break;
1468   }
1469 
1470   return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1471 }
1472 
CheckPPCBuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1473 bool Sema::CheckPPCBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1474   unsigned i = 0, l = 0, u = 0;
1475   bool Is64BitBltin = BuiltinID == PPC::BI__builtin_divde ||
1476                       BuiltinID == PPC::BI__builtin_divdeu ||
1477                       BuiltinID == PPC::BI__builtin_bpermd;
1478   bool IsTarget64Bit = Context.getTargetInfo()
1479                               .getTypeWidth(Context
1480                                             .getTargetInfo()
1481                                             .getIntPtrType()) == 64;
1482   bool IsBltinExtDiv = BuiltinID == PPC::BI__builtin_divwe ||
1483                        BuiltinID == PPC::BI__builtin_divweu ||
1484                        BuiltinID == PPC::BI__builtin_divde ||
1485                        BuiltinID == PPC::BI__builtin_divdeu;
1486 
1487   if (Is64BitBltin && !IsTarget64Bit)
1488       return Diag(TheCall->getLocStart(), diag::err_64_bit_builtin_32_bit_tgt)
1489              << TheCall->getSourceRange();
1490 
1491   if ((IsBltinExtDiv && !Context.getTargetInfo().hasFeature("extdiv")) ||
1492       (BuiltinID == PPC::BI__builtin_bpermd &&
1493        !Context.getTargetInfo().hasFeature("bpermd")))
1494     return Diag(TheCall->getLocStart(), diag::err_ppc_builtin_only_on_pwr7)
1495            << TheCall->getSourceRange();
1496 
1497   switch (BuiltinID) {
1498   default: return false;
1499   case PPC::BI__builtin_altivec_crypto_vshasigmaw:
1500   case PPC::BI__builtin_altivec_crypto_vshasigmad:
1501     return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
1502            SemaBuiltinConstantArgRange(TheCall, 2, 0, 15);
1503   case PPC::BI__builtin_tbegin:
1504   case PPC::BI__builtin_tend: i = 0; l = 0; u = 1; break;
1505   case PPC::BI__builtin_tsr: i = 0; l = 0; u = 7; break;
1506   case PPC::BI__builtin_tabortwc:
1507   case PPC::BI__builtin_tabortdc: i = 0; l = 0; u = 31; break;
1508   case PPC::BI__builtin_tabortwci:
1509   case PPC::BI__builtin_tabortdci:
1510     return SemaBuiltinConstantArgRange(TheCall, 0, 0, 31) ||
1511            SemaBuiltinConstantArgRange(TheCall, 2, 0, 31);
1512   }
1513   return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1514 }
1515 
CheckSystemZBuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1516 bool Sema::CheckSystemZBuiltinFunctionCall(unsigned BuiltinID,
1517                                            CallExpr *TheCall) {
1518   if (BuiltinID == SystemZ::BI__builtin_tabort) {
1519     Expr *Arg = TheCall->getArg(0);
1520     llvm::APSInt AbortCode(32);
1521     if (Arg->isIntegerConstantExpr(AbortCode, Context) &&
1522         AbortCode.getSExtValue() >= 0 && AbortCode.getSExtValue() < 256)
1523       return Diag(Arg->getLocStart(), diag::err_systemz_invalid_tabort_code)
1524              << Arg->getSourceRange();
1525   }
1526 
1527   // For intrinsics which take an immediate value as part of the instruction,
1528   // range check them here.
1529   unsigned i = 0, l = 0, u = 0;
1530   switch (BuiltinID) {
1531   default: return false;
1532   case SystemZ::BI__builtin_s390_lcbb: i = 1; l = 0; u = 15; break;
1533   case SystemZ::BI__builtin_s390_verimb:
1534   case SystemZ::BI__builtin_s390_verimh:
1535   case SystemZ::BI__builtin_s390_verimf:
1536   case SystemZ::BI__builtin_s390_verimg: i = 3; l = 0; u = 255; break;
1537   case SystemZ::BI__builtin_s390_vfaeb:
1538   case SystemZ::BI__builtin_s390_vfaeh:
1539   case SystemZ::BI__builtin_s390_vfaef:
1540   case SystemZ::BI__builtin_s390_vfaebs:
1541   case SystemZ::BI__builtin_s390_vfaehs:
1542   case SystemZ::BI__builtin_s390_vfaefs:
1543   case SystemZ::BI__builtin_s390_vfaezb:
1544   case SystemZ::BI__builtin_s390_vfaezh:
1545   case SystemZ::BI__builtin_s390_vfaezf:
1546   case SystemZ::BI__builtin_s390_vfaezbs:
1547   case SystemZ::BI__builtin_s390_vfaezhs:
1548   case SystemZ::BI__builtin_s390_vfaezfs: i = 2; l = 0; u = 15; break;
1549   case SystemZ::BI__builtin_s390_vfidb:
1550     return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15) ||
1551            SemaBuiltinConstantArgRange(TheCall, 2, 0, 15);
1552   case SystemZ::BI__builtin_s390_vftcidb: i = 1; l = 0; u = 4095; break;
1553   case SystemZ::BI__builtin_s390_vlbb: i = 1; l = 0; u = 15; break;
1554   case SystemZ::BI__builtin_s390_vpdi: i = 2; l = 0; u = 15; break;
1555   case SystemZ::BI__builtin_s390_vsldb: i = 2; l = 0; u = 15; break;
1556   case SystemZ::BI__builtin_s390_vstrcb:
1557   case SystemZ::BI__builtin_s390_vstrch:
1558   case SystemZ::BI__builtin_s390_vstrcf:
1559   case SystemZ::BI__builtin_s390_vstrczb:
1560   case SystemZ::BI__builtin_s390_vstrczh:
1561   case SystemZ::BI__builtin_s390_vstrczf:
1562   case SystemZ::BI__builtin_s390_vstrcbs:
1563   case SystemZ::BI__builtin_s390_vstrchs:
1564   case SystemZ::BI__builtin_s390_vstrcfs:
1565   case SystemZ::BI__builtin_s390_vstrczbs:
1566   case SystemZ::BI__builtin_s390_vstrczhs:
1567   case SystemZ::BI__builtin_s390_vstrczfs: i = 3; l = 0; u = 15; break;
1568   }
1569   return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1570 }
1571 
1572 /// SemaBuiltinCpuSupports - Handle __builtin_cpu_supports(char *).
1573 /// This checks that the target supports __builtin_cpu_supports and
1574 /// that the string argument is constant and valid.
SemaBuiltinCpuSupports(Sema & S,CallExpr * TheCall)1575 static bool SemaBuiltinCpuSupports(Sema &S, CallExpr *TheCall) {
1576   Expr *Arg = TheCall->getArg(0);
1577 
1578   // Check if the argument is a string literal.
1579   if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts()))
1580     return S.Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal)
1581            << Arg->getSourceRange();
1582 
1583   // Check the contents of the string.
1584   StringRef Feature =
1585       cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString();
1586   if (!S.Context.getTargetInfo().validateCpuSupports(Feature))
1587     return S.Diag(TheCall->getLocStart(), diag::err_invalid_cpu_supports)
1588            << Arg->getSourceRange();
1589   return false;
1590 }
1591 
CheckX86BuiltinFunctionCall(unsigned BuiltinID,CallExpr * TheCall)1592 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1593   int i = 0, l = 0, u = 0;
1594   switch (BuiltinID) {
1595   default:
1596     return false;
1597   case X86::BI__builtin_cpu_supports:
1598     return SemaBuiltinCpuSupports(*this, TheCall);
1599   case X86::BI__builtin_ms_va_start:
1600     return SemaBuiltinMSVAStart(TheCall);
1601   case X86::BI__builtin_ia32_extractf64x4_mask:
1602   case X86::BI__builtin_ia32_extracti64x4_mask:
1603   case X86::BI__builtin_ia32_extractf32x8_mask:
1604   case X86::BI__builtin_ia32_extracti32x8_mask:
1605   case X86::BI__builtin_ia32_extractf64x2_256_mask:
1606   case X86::BI__builtin_ia32_extracti64x2_256_mask:
1607   case X86::BI__builtin_ia32_extractf32x4_256_mask:
1608   case X86::BI__builtin_ia32_extracti32x4_256_mask:
1609     i = 1; l = 0; u = 1;
1610     break;
1611   case X86::BI_mm_prefetch:
1612   case X86::BI__builtin_ia32_extractf32x4_mask:
1613   case X86::BI__builtin_ia32_extracti32x4_mask:
1614   case X86::BI__builtin_ia32_extractf64x2_512_mask:
1615   case X86::BI__builtin_ia32_extracti64x2_512_mask:
1616     i = 1; l = 0; u = 3;
1617     break;
1618   case X86::BI__builtin_ia32_insertf32x8_mask:
1619   case X86::BI__builtin_ia32_inserti32x8_mask:
1620   case X86::BI__builtin_ia32_insertf64x4_mask:
1621   case X86::BI__builtin_ia32_inserti64x4_mask:
1622   case X86::BI__builtin_ia32_insertf64x2_256_mask:
1623   case X86::BI__builtin_ia32_inserti64x2_256_mask:
1624   case X86::BI__builtin_ia32_insertf32x4_256_mask:
1625   case X86::BI__builtin_ia32_inserti32x4_256_mask:
1626     i = 2; l = 0; u = 1;
1627     break;
1628   case X86::BI__builtin_ia32_sha1rnds4:
1629   case X86::BI__builtin_ia32_shuf_f32x4_256_mask:
1630   case X86::BI__builtin_ia32_shuf_f64x2_256_mask:
1631   case X86::BI__builtin_ia32_shuf_i32x4_256_mask:
1632   case X86::BI__builtin_ia32_shuf_i64x2_256_mask:
1633   case X86::BI__builtin_ia32_insertf64x2_512_mask:
1634   case X86::BI__builtin_ia32_inserti64x2_512_mask:
1635   case X86::BI__builtin_ia32_insertf32x4_mask:
1636   case X86::BI__builtin_ia32_inserti32x4_mask:
1637     i = 2; l = 0; u = 3;
1638     break;
1639   case X86::BI__builtin_ia32_vpermil2pd:
1640   case X86::BI__builtin_ia32_vpermil2pd256:
1641   case X86::BI__builtin_ia32_vpermil2ps:
1642   case X86::BI__builtin_ia32_vpermil2ps256:
1643     i = 3; l = 0; u = 3;
1644     break;
1645   case X86::BI__builtin_ia32_cmpb128_mask:
1646   case X86::BI__builtin_ia32_cmpw128_mask:
1647   case X86::BI__builtin_ia32_cmpd128_mask:
1648   case X86::BI__builtin_ia32_cmpq128_mask:
1649   case X86::BI__builtin_ia32_cmpb256_mask:
1650   case X86::BI__builtin_ia32_cmpw256_mask:
1651   case X86::BI__builtin_ia32_cmpd256_mask:
1652   case X86::BI__builtin_ia32_cmpq256_mask:
1653   case X86::BI__builtin_ia32_cmpb512_mask:
1654   case X86::BI__builtin_ia32_cmpw512_mask:
1655   case X86::BI__builtin_ia32_cmpd512_mask:
1656   case X86::BI__builtin_ia32_cmpq512_mask:
1657   case X86::BI__builtin_ia32_ucmpb128_mask:
1658   case X86::BI__builtin_ia32_ucmpw128_mask:
1659   case X86::BI__builtin_ia32_ucmpd128_mask:
1660   case X86::BI__builtin_ia32_ucmpq128_mask:
1661   case X86::BI__builtin_ia32_ucmpb256_mask:
1662   case X86::BI__builtin_ia32_ucmpw256_mask:
1663   case X86::BI__builtin_ia32_ucmpd256_mask:
1664   case X86::BI__builtin_ia32_ucmpq256_mask:
1665   case X86::BI__builtin_ia32_ucmpb512_mask:
1666   case X86::BI__builtin_ia32_ucmpw512_mask:
1667   case X86::BI__builtin_ia32_ucmpd512_mask:
1668   case X86::BI__builtin_ia32_ucmpq512_mask:
1669   case X86::BI__builtin_ia32_vpcomub:
1670   case X86::BI__builtin_ia32_vpcomuw:
1671   case X86::BI__builtin_ia32_vpcomud:
1672   case X86::BI__builtin_ia32_vpcomuq:
1673   case X86::BI__builtin_ia32_vpcomb:
1674   case X86::BI__builtin_ia32_vpcomw:
1675   case X86::BI__builtin_ia32_vpcomd:
1676   case X86::BI__builtin_ia32_vpcomq:
1677     i = 2; l = 0; u = 7;
1678     break;
1679   case X86::BI__builtin_ia32_roundps:
1680   case X86::BI__builtin_ia32_roundpd:
1681   case X86::BI__builtin_ia32_roundps256:
1682   case X86::BI__builtin_ia32_roundpd256:
1683     i = 1; l = 0; u = 15;
1684     break;
1685   case X86::BI__builtin_ia32_roundss:
1686   case X86::BI__builtin_ia32_roundsd:
1687   case X86::BI__builtin_ia32_rangepd128_mask:
1688   case X86::BI__builtin_ia32_rangepd256_mask:
1689   case X86::BI__builtin_ia32_rangepd512_mask:
1690   case X86::BI__builtin_ia32_rangeps128_mask:
1691   case X86::BI__builtin_ia32_rangeps256_mask:
1692   case X86::BI__builtin_ia32_rangeps512_mask:
1693   case X86::BI__builtin_ia32_getmantsd_round_mask:
1694   case X86::BI__builtin_ia32_getmantss_round_mask:
1695     i = 2; l = 0; u = 15;
1696     break;
1697   case X86::BI__builtin_ia32_cmpps:
1698   case X86::BI__builtin_ia32_cmpss:
1699   case X86::BI__builtin_ia32_cmppd:
1700   case X86::BI__builtin_ia32_cmpsd:
1701   case X86::BI__builtin_ia32_cmpps256:
1702   case X86::BI__builtin_ia32_cmppd256:
1703   case X86::BI__builtin_ia32_cmpps128_mask:
1704   case X86::BI__builtin_ia32_cmppd128_mask:
1705   case X86::BI__builtin_ia32_cmpps256_mask:
1706   case X86::BI__builtin_ia32_cmppd256_mask:
1707   case X86::BI__builtin_ia32_cmpps512_mask:
1708   case X86::BI__builtin_ia32_cmppd512_mask:
1709   case X86::BI__builtin_ia32_cmpsd_mask:
1710   case X86::BI__builtin_ia32_cmpss_mask:
1711     i = 2; l = 0; u = 31;
1712     break;
1713   case X86::BI__builtin_ia32_xabort:
1714     i = 0; l = -128; u = 255;
1715     break;
1716   case X86::BI__builtin_ia32_pshufw:
1717   case X86::BI__builtin_ia32_aeskeygenassist128:
1718     i = 1; l = -128; u = 255;
1719     break;
1720   case X86::BI__builtin_ia32_vcvtps2ph:
1721   case X86::BI__builtin_ia32_vcvtps2ph256:
1722   case X86::BI__builtin_ia32_rndscaleps_128_mask:
1723   case X86::BI__builtin_ia32_rndscalepd_128_mask:
1724   case X86::BI__builtin_ia32_rndscaleps_256_mask:
1725   case X86::BI__builtin_ia32_rndscalepd_256_mask:
1726   case X86::BI__builtin_ia32_rndscaleps_mask:
1727   case X86::BI__builtin_ia32_rndscalepd_mask:
1728   case X86::BI__builtin_ia32_reducepd128_mask:
1729   case X86::BI__builtin_ia32_reducepd256_mask:
1730   case X86::BI__builtin_ia32_reducepd512_mask:
1731   case X86::BI__builtin_ia32_reduceps128_mask:
1732   case X86::BI__builtin_ia32_reduceps256_mask:
1733   case X86::BI__builtin_ia32_reduceps512_mask:
1734   case X86::BI__builtin_ia32_prold512_mask:
1735   case X86::BI__builtin_ia32_prolq512_mask:
1736   case X86::BI__builtin_ia32_prold128_mask:
1737   case X86::BI__builtin_ia32_prold256_mask:
1738   case X86::BI__builtin_ia32_prolq128_mask:
1739   case X86::BI__builtin_ia32_prolq256_mask:
1740   case X86::BI__builtin_ia32_prord128_mask:
1741   case X86::BI__builtin_ia32_prord256_mask:
1742   case X86::BI__builtin_ia32_prorq128_mask:
1743   case X86::BI__builtin_ia32_prorq256_mask:
1744   case X86::BI__builtin_ia32_psllwi512_mask:
1745   case X86::BI__builtin_ia32_psllwi128_mask:
1746   case X86::BI__builtin_ia32_psllwi256_mask:
1747   case X86::BI__builtin_ia32_psrldi128_mask:
1748   case X86::BI__builtin_ia32_psrldi256_mask:
1749   case X86::BI__builtin_ia32_psrldi512_mask:
1750   case X86::BI__builtin_ia32_psrlqi128_mask:
1751   case X86::BI__builtin_ia32_psrlqi256_mask:
1752   case X86::BI__builtin_ia32_psrlqi512_mask:
1753   case X86::BI__builtin_ia32_psrawi512_mask:
1754   case X86::BI__builtin_ia32_psrawi128_mask:
1755   case X86::BI__builtin_ia32_psrawi256_mask:
1756   case X86::BI__builtin_ia32_psrlwi512_mask:
1757   case X86::BI__builtin_ia32_psrlwi128_mask:
1758   case X86::BI__builtin_ia32_psrlwi256_mask:
1759   case X86::BI__builtin_ia32_psradi128_mask:
1760   case X86::BI__builtin_ia32_psradi256_mask:
1761   case X86::BI__builtin_ia32_psradi512_mask:
1762   case X86::BI__builtin_ia32_psraqi128_mask:
1763   case X86::BI__builtin_ia32_psraqi256_mask:
1764   case X86::BI__builtin_ia32_psraqi512_mask:
1765   case X86::BI__builtin_ia32_pslldi128_mask:
1766   case X86::BI__builtin_ia32_pslldi256_mask:
1767   case X86::BI__builtin_ia32_pslldi512_mask:
1768   case X86::BI__builtin_ia32_psllqi128_mask:
1769   case X86::BI__builtin_ia32_psllqi256_mask:
1770   case X86::BI__builtin_ia32_psllqi512_mask:
1771   case X86::BI__builtin_ia32_fpclasspd128_mask:
1772   case X86::BI__builtin_ia32_fpclasspd256_mask:
1773   case X86::BI__builtin_ia32_fpclassps128_mask:
1774   case X86::BI__builtin_ia32_fpclassps256_mask:
1775   case X86::BI__builtin_ia32_fpclassps512_mask:
1776   case X86::BI__builtin_ia32_fpclasspd512_mask:
1777   case X86::BI__builtin_ia32_fpclasssd_mask:
1778   case X86::BI__builtin_ia32_fpclassss_mask:
1779     i = 1; l = 0; u = 255;
1780     break;
1781   case X86::BI__builtin_ia32_palignr:
1782   case X86::BI__builtin_ia32_insertps128:
1783   case X86::BI__builtin_ia32_dpps:
1784   case X86::BI__builtin_ia32_dppd:
1785   case X86::BI__builtin_ia32_dpps256:
1786   case X86::BI__builtin_ia32_mpsadbw128:
1787   case X86::BI__builtin_ia32_mpsadbw256:
1788   case X86::BI__builtin_ia32_pcmpistrm128:
1789   case X86::BI__builtin_ia32_pcmpistri128:
1790   case X86::BI__builtin_ia32_pcmpistria128:
1791   case X86::BI__builtin_ia32_pcmpistric128:
1792   case X86::BI__builtin_ia32_pcmpistrio128:
1793   case X86::BI__builtin_ia32_pcmpistris128:
1794   case X86::BI__builtin_ia32_pcmpistriz128:
1795   case X86::BI__builtin_ia32_pclmulqdq128:
1796   case X86::BI__builtin_ia32_vperm2f128_pd256:
1797   case X86::BI__builtin_ia32_vperm2f128_ps256:
1798   case X86::BI__builtin_ia32_vperm2f128_si256:
1799   case X86::BI__builtin_ia32_permti256:
1800     i = 2; l = -128; u = 255;
1801     break;
1802   case X86::BI__builtin_ia32_palignr128:
1803   case X86::BI__builtin_ia32_palignr256:
1804   case X86::BI__builtin_ia32_palignr128_mask:
1805   case X86::BI__builtin_ia32_palignr256_mask:
1806   case X86::BI__builtin_ia32_palignr512_mask:
1807   case X86::BI__builtin_ia32_alignq512_mask:
1808   case X86::BI__builtin_ia32_alignd512_mask:
1809   case X86::BI__builtin_ia32_alignd128_mask:
1810   case X86::BI__builtin_ia32_alignd256_mask:
1811   case X86::BI__builtin_ia32_alignq128_mask:
1812   case X86::BI__builtin_ia32_alignq256_mask:
1813   case X86::BI__builtin_ia32_vcomisd:
1814   case X86::BI__builtin_ia32_vcomiss:
1815   case X86::BI__builtin_ia32_shuf_f32x4_mask:
1816   case X86::BI__builtin_ia32_shuf_f64x2_mask:
1817   case X86::BI__builtin_ia32_shuf_i32x4_mask:
1818   case X86::BI__builtin_ia32_shuf_i64x2_mask:
1819   case X86::BI__builtin_ia32_dbpsadbw128_mask:
1820   case X86::BI__builtin_ia32_dbpsadbw256_mask:
1821   case X86::BI__builtin_ia32_dbpsadbw512_mask:
1822     i = 2; l = 0; u = 255;
1823     break;
1824   case X86::BI__builtin_ia32_fixupimmpd512_mask:
1825   case X86::BI__builtin_ia32_fixupimmpd512_maskz:
1826   case X86::BI__builtin_ia32_fixupimmps512_mask:
1827   case X86::BI__builtin_ia32_fixupimmps512_maskz:
1828   case X86::BI__builtin_ia32_fixupimmsd_mask:
1829   case X86::BI__builtin_ia32_fixupimmsd_maskz:
1830   case X86::BI__builtin_ia32_fixupimmss_mask:
1831   case X86::BI__builtin_ia32_fixupimmss_maskz:
1832   case X86::BI__builtin_ia32_fixupimmpd128_mask:
1833   case X86::BI__builtin_ia32_fixupimmpd128_maskz:
1834   case X86::BI__builtin_ia32_fixupimmpd256_mask:
1835   case X86::BI__builtin_ia32_fixupimmpd256_maskz:
1836   case X86::BI__builtin_ia32_fixupimmps128_mask:
1837   case X86::BI__builtin_ia32_fixupimmps128_maskz:
1838   case X86::BI__builtin_ia32_fixupimmps256_mask:
1839   case X86::BI__builtin_ia32_fixupimmps256_maskz:
1840   case X86::BI__builtin_ia32_pternlogd512_mask:
1841   case X86::BI__builtin_ia32_pternlogd512_maskz:
1842   case X86::BI__builtin_ia32_pternlogq512_mask:
1843   case X86::BI__builtin_ia32_pternlogq512_maskz:
1844   case X86::BI__builtin_ia32_pternlogd128_mask:
1845   case X86::BI__builtin_ia32_pternlogd128_maskz:
1846   case X86::BI__builtin_ia32_pternlogd256_mask:
1847   case X86::BI__builtin_ia32_pternlogd256_maskz:
1848   case X86::BI__builtin_ia32_pternlogq128_mask:
1849   case X86::BI__builtin_ia32_pternlogq128_maskz:
1850   case X86::BI__builtin_ia32_pternlogq256_mask:
1851   case X86::BI__builtin_ia32_pternlogq256_maskz:
1852     i = 3; l = 0; u = 255;
1853     break;
1854   case X86::BI__builtin_ia32_pcmpestrm128:
1855   case X86::BI__builtin_ia32_pcmpestri128:
1856   case X86::BI__builtin_ia32_pcmpestria128:
1857   case X86::BI__builtin_ia32_pcmpestric128:
1858   case X86::BI__builtin_ia32_pcmpestrio128:
1859   case X86::BI__builtin_ia32_pcmpestris128:
1860   case X86::BI__builtin_ia32_pcmpestriz128:
1861     i = 4; l = -128; u = 255;
1862     break;
1863   case X86::BI__builtin_ia32_rndscalesd_round_mask:
1864   case X86::BI__builtin_ia32_rndscaless_round_mask:
1865     i = 4; l = 0; u = 255;
1866     break;
1867   }
1868   return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1869 }
1870 
1871 /// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
1872 /// parameter with the FormatAttr's correct format_idx and firstDataArg.
1873 /// Returns true when the format fits the function and the FormatStringInfo has
1874 /// been populated.
getFormatStringInfo(const FormatAttr * Format,bool IsCXXMember,FormatStringInfo * FSI)1875 bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
1876                                FormatStringInfo *FSI) {
1877   FSI->HasVAListArg = Format->getFirstArg() == 0;
1878   FSI->FormatIdx = Format->getFormatIdx() - 1;
1879   FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
1880 
1881   // The way the format attribute works in GCC, the implicit this argument
1882   // of member functions is counted. However, it doesn't appear in our own
1883   // lists, so decrement format_idx in that case.
1884   if (IsCXXMember) {
1885     if(FSI->FormatIdx == 0)
1886       return false;
1887     --FSI->FormatIdx;
1888     if (FSI->FirstDataArg != 0)
1889       --FSI->FirstDataArg;
1890   }
1891   return true;
1892 }
1893 
1894 /// Checks if a the given expression evaluates to null.
1895 ///
1896 /// \brief Returns true if the value evaluates to null.
CheckNonNullExpr(Sema & S,const Expr * Expr)1897 static bool CheckNonNullExpr(Sema &S, const Expr *Expr) {
1898   // If the expression has non-null type, it doesn't evaluate to null.
1899   if (auto nullability
1900         = Expr->IgnoreImplicit()->getType()->getNullability(S.Context)) {
1901     if (*nullability == NullabilityKind::NonNull)
1902       return false;
1903   }
1904 
1905   // As a special case, transparent unions initialized with zero are
1906   // considered null for the purposes of the nonnull attribute.
1907   if (const RecordType *UT = Expr->getType()->getAsUnionType()) {
1908     if (UT->getDecl()->hasAttr<TransparentUnionAttr>())
1909       if (const CompoundLiteralExpr *CLE =
1910           dyn_cast<CompoundLiteralExpr>(Expr))
1911         if (const InitListExpr *ILE =
1912             dyn_cast<InitListExpr>(CLE->getInitializer()))
1913           Expr = ILE->getInit(0);
1914   }
1915 
1916   bool Result;
1917   return (!Expr->isValueDependent() &&
1918           Expr->EvaluateAsBooleanCondition(Result, S.Context) &&
1919           !Result);
1920 }
1921 
CheckNonNullArgument(Sema & S,const Expr * ArgExpr,SourceLocation CallSiteLoc)1922 static void CheckNonNullArgument(Sema &S,
1923                                  const Expr *ArgExpr,
1924                                  SourceLocation CallSiteLoc) {
1925   if (CheckNonNullExpr(S, ArgExpr))
1926     S.DiagRuntimeBehavior(CallSiteLoc, ArgExpr,
1927            S.PDiag(diag::warn_null_arg) << ArgExpr->getSourceRange());
1928 }
1929 
GetFormatNSStringIdx(const FormatAttr * Format,unsigned & Idx)1930 bool Sema::GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx) {
1931   FormatStringInfo FSI;
1932   if ((GetFormatStringType(Format) == FST_NSString) &&
1933       getFormatStringInfo(Format, false, &FSI)) {
1934     Idx = FSI.FormatIdx;
1935     return true;
1936   }
1937   return false;
1938 }
1939 /// \brief Diagnose use of %s directive in an NSString which is being passed
1940 /// as formatting string to formatting method.
1941 static void
DiagnoseCStringFormatDirectiveInCFAPI(Sema & S,const NamedDecl * FDecl,Expr ** Args,unsigned NumArgs)1942 DiagnoseCStringFormatDirectiveInCFAPI(Sema &S,
1943                                         const NamedDecl *FDecl,
1944                                         Expr **Args,
1945                                         unsigned NumArgs) {
1946   unsigned Idx = 0;
1947   bool Format = false;
1948   ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily();
1949   if (SFFamily == ObjCStringFormatFamily::SFF_CFString) {
1950     Idx = 2;
1951     Format = true;
1952   }
1953   else
1954     for (const auto *I : FDecl->specific_attrs<FormatAttr>()) {
1955       if (S.GetFormatNSStringIdx(I, Idx)) {
1956         Format = true;
1957         break;
1958       }
1959     }
1960   if (!Format || NumArgs <= Idx)
1961     return;
1962   const Expr *FormatExpr = Args[Idx];
1963   if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr))
1964     FormatExpr = CSCE->getSubExpr();
1965   const StringLiteral *FormatString;
1966   if (const ObjCStringLiteral *OSL =
1967       dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts()))
1968     FormatString = OSL->getString();
1969   else
1970     FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts());
1971   if (!FormatString)
1972     return;
1973   if (S.FormatStringHasSArg(FormatString)) {
1974     S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
1975       << "%s" << 1 << 1;
1976     S.Diag(FDecl->getLocation(), diag::note_entity_declared_at)
1977       << FDecl->getDeclName();
1978   }
1979 }
1980 
1981 /// Determine whether the given type has a non-null nullability annotation.
isNonNullType(ASTContext & ctx,QualType type)1982 static bool isNonNullType(ASTContext &ctx, QualType type) {
1983   if (auto nullability = type->getNullability(ctx))
1984     return *nullability == NullabilityKind::NonNull;
1985 
1986   return false;
1987 }
1988 
CheckNonNullArguments(Sema & S,const NamedDecl * FDecl,const FunctionProtoType * Proto,ArrayRef<const Expr * > Args,SourceLocation CallSiteLoc)1989 static void CheckNonNullArguments(Sema &S,
1990                                   const NamedDecl *FDecl,
1991                                   const FunctionProtoType *Proto,
1992                                   ArrayRef<const Expr *> Args,
1993                                   SourceLocation CallSiteLoc) {
1994   assert((FDecl || Proto) && "Need a function declaration or prototype");
1995 
1996   // Check the attributes attached to the method/function itself.
1997   llvm::SmallBitVector NonNullArgs;
1998   if (FDecl) {
1999     // Handle the nonnull attribute on the function/method declaration itself.
2000     for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) {
2001       if (!NonNull->args_size()) {
2002         // Easy case: all pointer arguments are nonnull.
2003         for (const auto *Arg : Args)
2004           if (S.isValidPointerAttrType(Arg->getType()))
2005             CheckNonNullArgument(S, Arg, CallSiteLoc);
2006         return;
2007       }
2008 
2009       for (unsigned Val : NonNull->args()) {
2010         if (Val >= Args.size())
2011           continue;
2012         if (NonNullArgs.empty())
2013           NonNullArgs.resize(Args.size());
2014         NonNullArgs.set(Val);
2015       }
2016     }
2017   }
2018 
2019   if (FDecl && (isa<FunctionDecl>(FDecl) || isa<ObjCMethodDecl>(FDecl))) {
2020     // Handle the nonnull attribute on the parameters of the
2021     // function/method.
2022     ArrayRef<ParmVarDecl*> parms;
2023     if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl))
2024       parms = FD->parameters();
2025     else
2026       parms = cast<ObjCMethodDecl>(FDecl)->parameters();
2027 
2028     unsigned ParamIndex = 0;
2029     for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end();
2030          I != E; ++I, ++ParamIndex) {
2031       const ParmVarDecl *PVD = *I;
2032       if (PVD->hasAttr<NonNullAttr>() ||
2033           isNonNullType(S.Context, PVD->getType())) {
2034         if (NonNullArgs.empty())
2035           NonNullArgs.resize(Args.size());
2036 
2037         NonNullArgs.set(ParamIndex);
2038       }
2039     }
2040   } else {
2041     // If we have a non-function, non-method declaration but no
2042     // function prototype, try to dig out the function prototype.
2043     if (!Proto) {
2044       if (const ValueDecl *VD = dyn_cast<ValueDecl>(FDecl)) {
2045         QualType type = VD->getType().getNonReferenceType();
2046         if (auto pointerType = type->getAs<PointerType>())
2047           type = pointerType->getPointeeType();
2048         else if (auto blockType = type->getAs<BlockPointerType>())
2049           type = blockType->getPointeeType();
2050         // FIXME: data member pointers?
2051 
2052         // Dig out the function prototype, if there is one.
2053         Proto = type->getAs<FunctionProtoType>();
2054       }
2055     }
2056 
2057     // Fill in non-null argument information from the nullability
2058     // information on the parameter types (if we have them).
2059     if (Proto) {
2060       unsigned Index = 0;
2061       for (auto paramType : Proto->getParamTypes()) {
2062         if (isNonNullType(S.Context, paramType)) {
2063           if (NonNullArgs.empty())
2064             NonNullArgs.resize(Args.size());
2065 
2066           NonNullArgs.set(Index);
2067         }
2068 
2069         ++Index;
2070       }
2071     }
2072   }
2073 
2074   // Check for non-null arguments.
2075   for (unsigned ArgIndex = 0, ArgIndexEnd = NonNullArgs.size();
2076        ArgIndex != ArgIndexEnd; ++ArgIndex) {
2077     if (NonNullArgs[ArgIndex])
2078       CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc);
2079   }
2080 }
2081 
2082 /// Handles the checks for format strings, non-POD arguments to vararg
2083 /// functions, and NULL arguments passed to non-NULL parameters.
checkCall(NamedDecl * FDecl,const FunctionProtoType * Proto,ArrayRef<const Expr * > Args,bool IsMemberFunction,SourceLocation Loc,SourceRange Range,VariadicCallType CallType)2084 void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
2085                      ArrayRef<const Expr *> Args, bool IsMemberFunction,
2086                      SourceLocation Loc, SourceRange Range,
2087                      VariadicCallType CallType) {
2088   // FIXME: We should check as much as we can in the template definition.
2089   if (CurContext->isDependentContext())
2090     return;
2091 
2092   // Printf and scanf checking.
2093   llvm::SmallBitVector CheckedVarArgs;
2094   if (FDecl) {
2095     for (const auto *I : FDecl->specific_attrs<FormatAttr>()) {
2096       // Only create vector if there are format attributes.
2097       CheckedVarArgs.resize(Args.size());
2098 
2099       CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range,
2100                            CheckedVarArgs);
2101     }
2102   }
2103 
2104   // Refuse POD arguments that weren't caught by the format string
2105   // checks above.
2106   if (CallType != VariadicDoesNotApply) {
2107     unsigned NumParams = Proto ? Proto->getNumParams()
2108                        : FDecl && isa<FunctionDecl>(FDecl)
2109                            ? cast<FunctionDecl>(FDecl)->getNumParams()
2110                        : FDecl && isa<ObjCMethodDecl>(FDecl)
2111                            ? cast<ObjCMethodDecl>(FDecl)->param_size()
2112                        : 0;
2113 
2114     for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) {
2115       // Args[ArgIdx] can be null in malformed code.
2116       if (const Expr *Arg = Args[ArgIdx]) {
2117         if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx])
2118           checkVariadicArgument(Arg, CallType);
2119       }
2120     }
2121   }
2122 
2123   if (FDecl || Proto) {
2124     CheckNonNullArguments(*this, FDecl, Proto, Args, Loc);
2125 
2126     // Type safety checking.
2127     if (FDecl) {
2128       for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>())
2129         CheckArgumentWithTypeTag(I, Args.data());
2130     }
2131   }
2132 }
2133 
2134 /// CheckConstructorCall - Check a constructor call for correctness and safety
2135 /// properties not enforced by the C type system.
CheckConstructorCall(FunctionDecl * FDecl,ArrayRef<const Expr * > Args,const FunctionProtoType * Proto,SourceLocation Loc)2136 void Sema::CheckConstructorCall(FunctionDecl *FDecl,
2137                                 ArrayRef<const Expr *> Args,
2138                                 const FunctionProtoType *Proto,
2139                                 SourceLocation Loc) {
2140   VariadicCallType CallType =
2141     Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
2142   checkCall(FDecl, Proto, Args, /*IsMemberFunction=*/true, Loc, SourceRange(),
2143             CallType);
2144 }
2145 
2146 /// CheckFunctionCall - Check a direct function call for various correctness
2147 /// and safety properties not strictly enforced by the C type system.
CheckFunctionCall(FunctionDecl * FDecl,CallExpr * TheCall,const FunctionProtoType * Proto)2148 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
2149                              const FunctionProtoType *Proto) {
2150   bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) &&
2151                               isa<CXXMethodDecl>(FDecl);
2152   bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) ||
2153                           IsMemberOperatorCall;
2154   VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
2155                                                   TheCall->getCallee());
2156   Expr** Args = TheCall->getArgs();
2157   unsigned NumArgs = TheCall->getNumArgs();
2158   if (IsMemberOperatorCall) {
2159     // If this is a call to a member operator, hide the first argument
2160     // from checkCall.
2161     // FIXME: Our choice of AST representation here is less than ideal.
2162     ++Args;
2163     --NumArgs;
2164   }
2165   checkCall(FDecl, Proto, llvm::makeArrayRef(Args, NumArgs),
2166             IsMemberFunction, TheCall->getRParenLoc(),
2167             TheCall->getCallee()->getSourceRange(), CallType);
2168 
2169   IdentifierInfo *FnInfo = FDecl->getIdentifier();
2170   // None of the checks below are needed for functions that don't have
2171   // simple names (e.g., C++ conversion functions).
2172   if (!FnInfo)
2173     return false;
2174 
2175   CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo);
2176   if (getLangOpts().ObjC1)
2177     DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs);
2178 
2179   unsigned CMId = FDecl->getMemoryFunctionKind();
2180   if (CMId == 0)
2181     return false;
2182 
2183   // Handle memory setting and copying functions.
2184   if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
2185     CheckStrlcpycatArguments(TheCall, FnInfo);
2186   else if (CMId == Builtin::BIstrncat)
2187     CheckStrncatArguments(TheCall, FnInfo);
2188   else
2189     CheckMemaccessArguments(TheCall, CMId, FnInfo);
2190 
2191   return false;
2192 }
2193 
CheckObjCMethodCall(ObjCMethodDecl * Method,SourceLocation lbrac,ArrayRef<const Expr * > Args)2194 bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
2195                                ArrayRef<const Expr *> Args) {
2196   VariadicCallType CallType =
2197       Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
2198 
2199   checkCall(Method, nullptr, Args,
2200             /*IsMemberFunction=*/false, lbrac, Method->getSourceRange(),
2201             CallType);
2202 
2203   return false;
2204 }
2205 
CheckPointerCall(NamedDecl * NDecl,CallExpr * TheCall,const FunctionProtoType * Proto)2206 bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
2207                             const FunctionProtoType *Proto) {
2208   QualType Ty;
2209   if (const auto *V = dyn_cast<VarDecl>(NDecl))
2210     Ty = V->getType().getNonReferenceType();
2211   else if (const auto *F = dyn_cast<FieldDecl>(NDecl))
2212     Ty = F->getType().getNonReferenceType();
2213   else
2214     return false;
2215 
2216   if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType() &&
2217       !Ty->isFunctionProtoType())
2218     return false;
2219 
2220   VariadicCallType CallType;
2221   if (!Proto || !Proto->isVariadic()) {
2222     CallType = VariadicDoesNotApply;
2223   } else if (Ty->isBlockPointerType()) {
2224     CallType = VariadicBlock;
2225   } else { // Ty->isFunctionPointerType()
2226     CallType = VariadicFunction;
2227   }
2228 
2229   checkCall(NDecl, Proto,
2230             llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()),
2231             /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
2232             TheCall->getCallee()->getSourceRange(), CallType);
2233 
2234   return false;
2235 }
2236 
2237 /// Checks function calls when a FunctionDecl or a NamedDecl is not available,
2238 /// such as function pointers returned from functions.
CheckOtherCall(CallExpr * TheCall,const FunctionProtoType * Proto)2239 bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) {
2240   VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto,
2241                                                   TheCall->getCallee());
2242   checkCall(/*FDecl=*/nullptr, Proto,
2243             llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()),
2244             /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
2245             TheCall->getCallee()->getSourceRange(), CallType);
2246 
2247   return false;
2248 }
2249 
isValidOrderingForOp(int64_t Ordering,AtomicExpr::AtomicOp Op)2250 static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) {
2251   if (!llvm::isValidAtomicOrderingCABI(Ordering))
2252     return false;
2253 
2254   auto OrderingCABI = (llvm::AtomicOrderingCABI)Ordering;
2255   switch (Op) {
2256   case AtomicExpr::AO__c11_atomic_init:
2257     llvm_unreachable("There is no ordering argument for an init");
2258 
2259   case AtomicExpr::AO__c11_atomic_load:
2260   case AtomicExpr::AO__atomic_load_n:
2261   case AtomicExpr::AO__atomic_load:
2262     return OrderingCABI != llvm::AtomicOrderingCABI::release &&
2263            OrderingCABI != llvm::AtomicOrderingCABI::acq_rel;
2264 
2265   case AtomicExpr::AO__c11_atomic_store:
2266   case AtomicExpr::AO__atomic_store:
2267   case AtomicExpr::AO__atomic_store_n:
2268     return OrderingCABI != llvm::AtomicOrderingCABI::consume &&
2269            OrderingCABI != llvm::AtomicOrderingCABI::acquire &&
2270            OrderingCABI != llvm::AtomicOrderingCABI::acq_rel;
2271 
2272   default:
2273     return true;
2274   }
2275 }
2276 
SemaAtomicOpsOverloaded(ExprResult TheCallResult,AtomicExpr::AtomicOp Op)2277 ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
2278                                          AtomicExpr::AtomicOp Op) {
2279   CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
2280   DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
2281 
2282   // All these operations take one of the following forms:
2283   enum {
2284     // C    __c11_atomic_init(A *, C)
2285     Init,
2286     // C    __c11_atomic_load(A *, int)
2287     Load,
2288     // void __atomic_load(A *, CP, int)
2289     LoadCopy,
2290     // void __atomic_store(A *, CP, int)
2291     Copy,
2292     // C    __c11_atomic_add(A *, M, int)
2293     Arithmetic,
2294     // C    __atomic_exchange_n(A *, CP, int)
2295     Xchg,
2296     // void __atomic_exchange(A *, C *, CP, int)
2297     GNUXchg,
2298     // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
2299     C11CmpXchg,
2300     // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
2301     GNUCmpXchg
2302   } Form = Init;
2303   const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 3, 4, 5, 6 };
2304   const unsigned NumVals[] = { 1, 0, 1, 1, 1, 1, 2, 2, 3 };
2305   // where:
2306   //   C is an appropriate type,
2307   //   A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
2308   //   CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
2309   //   M is C if C is an integer, and ptrdiff_t if C is a pointer, and
2310   //   the int parameters are for orderings.
2311 
2312   static_assert(AtomicExpr::AO__c11_atomic_init == 0 &&
2313                     AtomicExpr::AO__c11_atomic_fetch_xor + 1 ==
2314                         AtomicExpr::AO__atomic_load,
2315                 "need to update code for modified C11 atomics");
2316   bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
2317                Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
2318   bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
2319              Op == AtomicExpr::AO__atomic_store_n ||
2320              Op == AtomicExpr::AO__atomic_exchange_n ||
2321              Op == AtomicExpr::AO__atomic_compare_exchange_n;
2322   bool IsAddSub = false;
2323 
2324   switch (Op) {
2325   case AtomicExpr::AO__c11_atomic_init:
2326     Form = Init;
2327     break;
2328 
2329   case AtomicExpr::AO__c11_atomic_load:
2330   case AtomicExpr::AO__atomic_load_n:
2331     Form = Load;
2332     break;
2333 
2334   case AtomicExpr::AO__atomic_load:
2335     Form = LoadCopy;
2336     break;
2337 
2338   case AtomicExpr::AO__c11_atomic_store:
2339   case AtomicExpr::AO__atomic_store:
2340   case AtomicExpr::AO__atomic_store_n:
2341     Form = Copy;
2342     break;
2343 
2344   case AtomicExpr::AO__c11_atomic_fetch_add:
2345   case AtomicExpr::AO__c11_atomic_fetch_sub:
2346   case AtomicExpr::AO__atomic_fetch_add:
2347   case AtomicExpr::AO__atomic_fetch_sub:
2348   case AtomicExpr::AO__atomic_add_fetch:
2349   case AtomicExpr::AO__atomic_sub_fetch:
2350     IsAddSub = true;
2351     // Fall through.
2352   case AtomicExpr::AO__c11_atomic_fetch_and:
2353   case AtomicExpr::AO__c11_atomic_fetch_or:
2354   case AtomicExpr::AO__c11_atomic_fetch_xor:
2355   case AtomicExpr::AO__atomic_fetch_and:
2356   case AtomicExpr::AO__atomic_fetch_or:
2357   case AtomicExpr::AO__atomic_fetch_xor:
2358   case AtomicExpr::AO__atomic_fetch_nand:
2359   case AtomicExpr::AO__atomic_and_fetch:
2360   case AtomicExpr::AO__atomic_or_fetch:
2361   case AtomicExpr::AO__atomic_xor_fetch:
2362   case AtomicExpr::AO__atomic_nand_fetch:
2363     Form = Arithmetic;
2364     break;
2365 
2366   case AtomicExpr::AO__c11_atomic_exchange:
2367   case AtomicExpr::AO__atomic_exchange_n:
2368     Form = Xchg;
2369     break;
2370 
2371   case AtomicExpr::AO__atomic_exchange:
2372     Form = GNUXchg;
2373     break;
2374 
2375   case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
2376   case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
2377     Form = C11CmpXchg;
2378     break;
2379 
2380   case AtomicExpr::AO__atomic_compare_exchange:
2381   case AtomicExpr::AO__atomic_compare_exchange_n:
2382     Form = GNUCmpXchg;
2383     break;
2384   }
2385 
2386   // Check we have the right number of arguments.
2387   if (TheCall->getNumArgs() < NumArgs[Form]) {
2388     Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
2389       << 0 << NumArgs[Form] << TheCall->getNumArgs()
2390       << TheCall->getCallee()->getSourceRange();
2391     return ExprError();
2392   } else if (TheCall->getNumArgs() > NumArgs[Form]) {
2393     Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
2394          diag::err_typecheck_call_too_many_args)
2395       << 0 << NumArgs[Form] << TheCall->getNumArgs()
2396       << TheCall->getCallee()->getSourceRange();
2397     return ExprError();
2398   }
2399 
2400   // Inspect the first argument of the atomic operation.
2401   Expr *Ptr = TheCall->getArg(0);
2402   Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
2403   const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
2404   if (!pointerType) {
2405     Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
2406       << Ptr->getType() << Ptr->getSourceRange();
2407     return ExprError();
2408   }
2409 
2410   // For a __c11 builtin, this should be a pointer to an _Atomic type.
2411   QualType AtomTy = pointerType->getPointeeType(); // 'A'
2412   QualType ValType = AtomTy; // 'C'
2413   if (IsC11) {
2414     if (!AtomTy->isAtomicType()) {
2415       Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
2416         << Ptr->getType() << Ptr->getSourceRange();
2417       return ExprError();
2418     }
2419     if (AtomTy.isConstQualified()) {
2420       Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
2421         << Ptr->getType() << Ptr->getSourceRange();
2422       return ExprError();
2423     }
2424     ValType = AtomTy->getAs<AtomicType>()->getValueType();
2425   } else if (Form != Load && Form != LoadCopy) {
2426     if (ValType.isConstQualified()) {
2427       Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_pointer)
2428         << Ptr->getType() << Ptr->getSourceRange();
2429       return ExprError();
2430     }
2431   }
2432 
2433   // For an arithmetic operation, the implied arithmetic must be well-formed.
2434   if (Form == Arithmetic) {
2435     // gcc does not enforce these rules for GNU atomics, but we do so for sanity.
2436     if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
2437       Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
2438         << IsC11 << Ptr->getType() << Ptr->getSourceRange();
2439       return ExprError();
2440     }
2441     if (!IsAddSub && !ValType->isIntegerType()) {
2442       Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
2443         << IsC11 << Ptr->getType() << Ptr->getSourceRange();
2444       return ExprError();
2445     }
2446     if (IsC11 && ValType->isPointerType() &&
2447         RequireCompleteType(Ptr->getLocStart(), ValType->getPointeeType(),
2448                             diag::err_incomplete_type)) {
2449       return ExprError();
2450     }
2451   } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
2452     // For __atomic_*_n operations, the value type must be a scalar integral or
2453     // pointer type which is 1, 2, 4, 8 or 16 bytes in length.
2454     Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
2455       << IsC11 << Ptr->getType() << Ptr->getSourceRange();
2456     return ExprError();
2457   }
2458 
2459   if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) &&
2460       !AtomTy->isScalarType()) {
2461     // For GNU atomics, require a trivially-copyable type. This is not part of
2462     // the GNU atomics specification, but we enforce it for sanity.
2463     Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
2464       << Ptr->getType() << Ptr->getSourceRange();
2465     return ExprError();
2466   }
2467 
2468   switch (ValType.getObjCLifetime()) {
2469   case Qualifiers::OCL_None:
2470   case Qualifiers::OCL_ExplicitNone:
2471     // okay
2472     break;
2473 
2474   case Qualifiers::OCL_Weak:
2475   case Qualifiers::OCL_Strong:
2476   case Qualifiers::OCL_Autoreleasing:
2477     // FIXME: Can this happen? By this point, ValType should be known
2478     // to be trivially copyable.
2479     Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
2480       << ValType << Ptr->getSourceRange();
2481     return ExprError();
2482   }
2483 
2484   // atomic_fetch_or takes a pointer to a volatile 'A'.  We shouldn't let the
2485   // volatile-ness of the pointee-type inject itself into the result or the
2486   // other operands. Similarly atomic_load can take a pointer to a const 'A'.
2487   ValType.removeLocalVolatile();
2488   ValType.removeLocalConst();
2489   QualType ResultType = ValType;
2490   if (Form == Copy || Form == LoadCopy || Form == GNUXchg || Form == Init)
2491     ResultType = Context.VoidTy;
2492   else if (Form == C11CmpXchg || Form == GNUCmpXchg)
2493     ResultType = Context.BoolTy;
2494 
2495   // The type of a parameter passed 'by value'. In the GNU atomics, such
2496   // arguments are actually passed as pointers.
2497   QualType ByValType = ValType; // 'CP'
2498   if (!IsC11 && !IsN)
2499     ByValType = Ptr->getType();
2500 
2501   // The first argument --- the pointer --- has a fixed type; we
2502   // deduce the types of the rest of the arguments accordingly.  Walk
2503   // the remaining arguments, converting them to the deduced value type.
2504   for (unsigned i = 1; i != NumArgs[Form]; ++i) {
2505     QualType Ty;
2506     if (i < NumVals[Form] + 1) {
2507       switch (i) {
2508       case 1:
2509         // The second argument is the non-atomic operand. For arithmetic, this
2510         // is always passed by value, and for a compare_exchange it is always
2511         // passed by address. For the rest, GNU uses by-address and C11 uses
2512         // by-value.
2513         assert(Form != Load);
2514         if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
2515           Ty = ValType;
2516         else if (Form == Copy || Form == Xchg)
2517           Ty = ByValType;
2518         else if (Form == Arithmetic)
2519           Ty = Context.getPointerDiffType();
2520         else {
2521           Expr *ValArg = TheCall->getArg(i);
2522           unsigned AS = 0;
2523           // Keep address space of non-atomic pointer type.
2524           if (const PointerType *PtrTy =
2525                   ValArg->getType()->getAs<PointerType>()) {
2526             AS = PtrTy->getPointeeType().getAddressSpace();
2527           }
2528           Ty = Context.getPointerType(
2529               Context.getAddrSpaceQualType(ValType.getUnqualifiedType(), AS));
2530         }
2531         break;
2532       case 2:
2533         // The third argument to compare_exchange / GNU exchange is a
2534         // (pointer to a) desired value.
2535         Ty = ByValType;
2536         break;
2537       case 3:
2538         // The fourth argument to GNU compare_exchange is a 'weak' flag.
2539         Ty = Context.BoolTy;
2540         break;
2541       }
2542     } else {
2543       // The order(s) are always converted to int.
2544       Ty = Context.IntTy;
2545     }
2546 
2547     InitializedEntity Entity =
2548         InitializedEntity::InitializeParameter(Context, Ty, false);
2549     ExprResult Arg = TheCall->getArg(i);
2550     Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
2551     if (Arg.isInvalid())
2552       return true;
2553     TheCall->setArg(i, Arg.get());
2554   }
2555 
2556   // Permute the arguments into a 'consistent' order.
2557   SmallVector<Expr*, 5> SubExprs;
2558   SubExprs.push_back(Ptr);
2559   switch (Form) {
2560   case Init:
2561     // Note, AtomicExpr::getVal1() has a special case for this atomic.
2562     SubExprs.push_back(TheCall->getArg(1)); // Val1
2563     break;
2564   case Load:
2565     SubExprs.push_back(TheCall->getArg(1)); // Order
2566     break;
2567   case LoadCopy:
2568   case Copy:
2569   case Arithmetic:
2570   case Xchg:
2571     SubExprs.push_back(TheCall->getArg(2)); // Order
2572     SubExprs.push_back(TheCall->getArg(1)); // Val1
2573     break;
2574   case GNUXchg:
2575     // Note, AtomicExpr::getVal2() has a special case for this atomic.
2576     SubExprs.push_back(TheCall->getArg(3)); // Order
2577     SubExprs.push_back(TheCall->getArg(1)); // Val1
2578     SubExprs.push_back(TheCall->getArg(2)); // Val2
2579     break;
2580   case C11CmpXchg:
2581     SubExprs.push_back(TheCall->getArg(3)); // Order
2582     SubExprs.push_back(TheCall->getArg(1)); // Val1
2583     SubExprs.push_back(TheCall->getArg(4)); // OrderFail
2584     SubExprs.push_back(TheCall->getArg(2)); // Val2
2585     break;
2586   case GNUCmpXchg:
2587     SubExprs.push_back(TheCall->getArg(4)); // Order
2588     SubExprs.push_back(TheCall->getArg(1)); // Val1
2589     SubExprs.push_back(TheCall->getArg(5)); // OrderFail
2590     SubExprs.push_back(TheCall->getArg(2)); // Val2
2591     SubExprs.push_back(TheCall->getArg(3)); // Weak
2592     break;
2593   }
2594 
2595   if (SubExprs.size() >= 2 && Form != Init) {
2596     llvm::APSInt Result(32);
2597     if (SubExprs[1]->isIntegerConstantExpr(Result, Context) &&
2598         !isValidOrderingForOp(Result.getSExtValue(), Op))
2599       Diag(SubExprs[1]->getLocStart(),
2600            diag::warn_atomic_op_has_invalid_memory_order)
2601           << SubExprs[1]->getSourceRange();
2602   }
2603 
2604   AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
2605                                             SubExprs, ResultType, Op,
2606                                             TheCall->getRParenLoc());
2607 
2608   if ((Op == AtomicExpr::AO__c11_atomic_load ||
2609        (Op == AtomicExpr::AO__c11_atomic_store)) &&
2610       Context.AtomicUsesUnsupportedLibcall(AE))
2611     Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) <<
2612     ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1);
2613 
2614   return AE;
2615 }
2616 
2617 /// checkBuiltinArgument - Given a call to a builtin function, perform
2618 /// normal type-checking on the given argument, updating the call in
2619 /// place.  This is useful when a builtin function requires custom
2620 /// type-checking for some of its arguments but not necessarily all of
2621 /// them.
2622 ///
2623 /// Returns true on error.
checkBuiltinArgument(Sema & S,CallExpr * E,unsigned ArgIndex)2624 static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
2625   FunctionDecl *Fn = E->getDirectCallee();
2626   assert(Fn && "builtin call without direct callee!");
2627 
2628   ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
2629   InitializedEntity Entity =
2630     InitializedEntity::InitializeParameter(S.Context, Param);
2631 
2632   ExprResult Arg = E->getArg(0);
2633   Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
2634   if (Arg.isInvalid())
2635     return true;
2636 
2637   E->setArg(ArgIndex, Arg.get());
2638   return false;
2639 }
2640 
2641 /// SemaBuiltinAtomicOverloaded - We have a call to a function like
2642 /// __sync_fetch_and_add, which is an overloaded function based on the pointer
2643 /// type of its first argument.  The main ActOnCallExpr routines have already
2644 /// promoted the types of arguments because all of these calls are prototyped as
2645 /// void(...).
2646 ///
2647 /// This function goes through and does final semantic checking for these
2648 /// builtins,
2649 ExprResult
SemaBuiltinAtomicOverloaded(ExprResult TheCallResult)2650 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
2651   CallExpr *TheCall = (CallExpr *)TheCallResult.get();
2652   DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
2653   FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
2654 
2655   // Ensure that we have at least one argument to do type inference from.
2656   if (TheCall->getNumArgs() < 1) {
2657     Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
2658       << 0 << 1 << TheCall->getNumArgs()
2659       << TheCall->getCallee()->getSourceRange();
2660     return ExprError();
2661   }
2662 
2663   // Inspect the first argument of the atomic builtin.  This should always be
2664   // a pointer type, whose element is an integral scalar or pointer type.
2665   // Because it is a pointer type, we don't have to worry about any implicit
2666   // casts here.
2667   // FIXME: We don't allow floating point scalars as input.
2668   Expr *FirstArg = TheCall->getArg(0);
2669   ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
2670   if (FirstArgResult.isInvalid())
2671     return ExprError();
2672   FirstArg = FirstArgResult.get();
2673   TheCall->setArg(0, FirstArg);
2674 
2675   const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
2676   if (!pointerType) {
2677     Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
2678       << FirstArg->getType() << FirstArg->getSourceRange();
2679     return ExprError();
2680   }
2681 
2682   QualType ValType = pointerType->getPointeeType();
2683   if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
2684       !ValType->isBlockPointerType()) {
2685     Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
2686       << FirstArg->getType() << FirstArg->getSourceRange();
2687     return ExprError();
2688   }
2689 
2690   switch (ValType.getObjCLifetime()) {
2691   case Qualifiers::OCL_None:
2692   case Qualifiers::OCL_ExplicitNone:
2693     // okay
2694     break;
2695 
2696   case Qualifiers::OCL_Weak:
2697   case Qualifiers::OCL_Strong:
2698   case Qualifiers::OCL_Autoreleasing:
2699     Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
2700       << ValType << FirstArg->getSourceRange();
2701     return ExprError();
2702   }
2703 
2704   // Strip any qualifiers off ValType.
2705   ValType = ValType.getUnqualifiedType();
2706 
2707   // The majority of builtins return a value, but a few have special return
2708   // types, so allow them to override appropriately below.
2709   QualType ResultType = ValType;
2710 
2711   // We need to figure out which concrete builtin this maps onto.  For example,
2712   // __sync_fetch_and_add with a 2 byte object turns into
2713   // __sync_fetch_and_add_2.
2714 #define BUILTIN_ROW(x) \
2715   { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
2716     Builtin::BI##x##_8, Builtin::BI##x##_16 }
2717 
2718   static const unsigned BuiltinIndices[][5] = {
2719     BUILTIN_ROW(__sync_fetch_and_add),
2720     BUILTIN_ROW(__sync_fetch_and_sub),
2721     BUILTIN_ROW(__sync_fetch_and_or),
2722     BUILTIN_ROW(__sync_fetch_and_and),
2723     BUILTIN_ROW(__sync_fetch_and_xor),
2724     BUILTIN_ROW(__sync_fetch_and_nand),
2725 
2726     BUILTIN_ROW(__sync_add_and_fetch),
2727     BUILTIN_ROW(__sync_sub_and_fetch),
2728     BUILTIN_ROW(__sync_and_and_fetch),
2729     BUILTIN_ROW(__sync_or_and_fetch),
2730     BUILTIN_ROW(__sync_xor_and_fetch),
2731     BUILTIN_ROW(__sync_nand_and_fetch),
2732 
2733     BUILTIN_ROW(__sync_val_compare_and_swap),
2734     BUILTIN_ROW(__sync_bool_compare_and_swap),
2735     BUILTIN_ROW(__sync_lock_test_and_set),
2736     BUILTIN_ROW(__sync_lock_release),
2737     BUILTIN_ROW(__sync_swap)
2738   };
2739 #undef BUILTIN_ROW
2740 
2741   // Determine the index of the size.
2742   unsigned SizeIndex;
2743   switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
2744   case 1: SizeIndex = 0; break;
2745   case 2: SizeIndex = 1; break;
2746   case 4: SizeIndex = 2; break;
2747   case 8: SizeIndex = 3; break;
2748   case 16: SizeIndex = 4; break;
2749   default:
2750     Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
2751       << FirstArg->getType() << FirstArg->getSourceRange();
2752     return ExprError();
2753   }
2754 
2755   // Each of these builtins has one pointer argument, followed by some number of
2756   // values (0, 1 or 2) followed by a potentially empty varags list of stuff
2757   // that we ignore.  Find out which row of BuiltinIndices to read from as well
2758   // as the number of fixed args.
2759   unsigned BuiltinID = FDecl->getBuiltinID();
2760   unsigned BuiltinIndex, NumFixed = 1;
2761   bool WarnAboutSemanticsChange = false;
2762   switch (BuiltinID) {
2763   default: llvm_unreachable("Unknown overloaded atomic builtin!");
2764   case Builtin::BI__sync_fetch_and_add:
2765   case Builtin::BI__sync_fetch_and_add_1:
2766   case Builtin::BI__sync_fetch_and_add_2:
2767   case Builtin::BI__sync_fetch_and_add_4:
2768   case Builtin::BI__sync_fetch_and_add_8:
2769   case Builtin::BI__sync_fetch_and_add_16:
2770     BuiltinIndex = 0;
2771     break;
2772 
2773   case Builtin::BI__sync_fetch_and_sub:
2774   case Builtin::BI__sync_fetch_and_sub_1:
2775   case Builtin::BI__sync_fetch_and_sub_2:
2776   case Builtin::BI__sync_fetch_and_sub_4:
2777   case Builtin::BI__sync_fetch_and_sub_8:
2778   case Builtin::BI__sync_fetch_and_sub_16:
2779     BuiltinIndex = 1;
2780     break;
2781 
2782   case Builtin::BI__sync_fetch_and_or:
2783   case Builtin::BI__sync_fetch_and_or_1:
2784   case Builtin::BI__sync_fetch_and_or_2:
2785   case Builtin::BI__sync_fetch_and_or_4:
2786   case Builtin::BI__sync_fetch_and_or_8:
2787   case Builtin::BI__sync_fetch_and_or_16:
2788     BuiltinIndex = 2;
2789     break;
2790 
2791   case Builtin::BI__sync_fetch_and_and:
2792   case Builtin::BI__sync_fetch_and_and_1:
2793   case Builtin::BI__sync_fetch_and_and_2:
2794   case Builtin::BI__sync_fetch_and_and_4:
2795   case Builtin::BI__sync_fetch_and_and_8:
2796   case Builtin::BI__sync_fetch_and_and_16:
2797     BuiltinIndex = 3;
2798     break;
2799 
2800   case Builtin::BI__sync_fetch_and_xor:
2801   case Builtin::BI__sync_fetch_and_xor_1:
2802   case Builtin::BI__sync_fetch_and_xor_2:
2803   case Builtin::BI__sync_fetch_and_xor_4:
2804   case Builtin::BI__sync_fetch_and_xor_8:
2805   case Builtin::BI__sync_fetch_and_xor_16:
2806     BuiltinIndex = 4;
2807     break;
2808 
2809   case Builtin::BI__sync_fetch_and_nand:
2810   case Builtin::BI__sync_fetch_and_nand_1:
2811   case Builtin::BI__sync_fetch_and_nand_2:
2812   case Builtin::BI__sync_fetch_and_nand_4:
2813   case Builtin::BI__sync_fetch_and_nand_8:
2814   case Builtin::BI__sync_fetch_and_nand_16:
2815     BuiltinIndex = 5;
2816     WarnAboutSemanticsChange = true;
2817     break;
2818 
2819   case Builtin::BI__sync_add_and_fetch:
2820   case Builtin::BI__sync_add_and_fetch_1:
2821   case Builtin::BI__sync_add_and_fetch_2:
2822   case Builtin::BI__sync_add_and_fetch_4:
2823   case Builtin::BI__sync_add_and_fetch_8:
2824   case Builtin::BI__sync_add_and_fetch_16:
2825     BuiltinIndex = 6;
2826     break;
2827 
2828   case Builtin::BI__sync_sub_and_fetch:
2829   case Builtin::BI__sync_sub_and_fetch_1:
2830   case Builtin::BI__sync_sub_and_fetch_2:
2831   case Builtin::BI__sync_sub_and_fetch_4:
2832   case Builtin::BI__sync_sub_and_fetch_8:
2833   case Builtin::BI__sync_sub_and_fetch_16:
2834     BuiltinIndex = 7;
2835     break;
2836 
2837   case Builtin::BI__sync_and_and_fetch:
2838   case Builtin::BI__sync_and_and_fetch_1:
2839   case Builtin::BI__sync_and_and_fetch_2:
2840   case Builtin::BI__sync_and_and_fetch_4:
2841   case Builtin::BI__sync_and_and_fetch_8:
2842   case Builtin::BI__sync_and_and_fetch_16:
2843     BuiltinIndex = 8;
2844     break;
2845 
2846   case Builtin::BI__sync_or_and_fetch:
2847   case Builtin::BI__sync_or_and_fetch_1:
2848   case Builtin::BI__sync_or_and_fetch_2:
2849   case Builtin::BI__sync_or_and_fetch_4:
2850   case Builtin::BI__sync_or_and_fetch_8:
2851   case Builtin::BI__sync_or_and_fetch_16:
2852     BuiltinIndex = 9;
2853     break;
2854 
2855   case Builtin::BI__sync_xor_and_fetch:
2856   case Builtin::BI__sync_xor_and_fetch_1:
2857   case Builtin::BI__sync_xor_and_fetch_2:
2858   case Builtin::BI__sync_xor_and_fetch_4:
2859   case Builtin::BI__sync_xor_and_fetch_8:
2860   case Builtin::BI__sync_xor_and_fetch_16:
2861     BuiltinIndex = 10;
2862     break;
2863 
2864   case Builtin::BI__sync_nand_and_fetch:
2865   case Builtin::BI__sync_nand_and_fetch_1:
2866   case Builtin::BI__sync_nand_and_fetch_2:
2867   case Builtin::BI__sync_nand_and_fetch_4:
2868   case Builtin::BI__sync_nand_and_fetch_8:
2869   case Builtin::BI__sync_nand_and_fetch_16:
2870     BuiltinIndex = 11;
2871     WarnAboutSemanticsChange = true;
2872     break;
2873 
2874   case Builtin::BI__sync_val_compare_and_swap:
2875   case Builtin::BI__sync_val_compare_and_swap_1:
2876   case Builtin::BI__sync_val_compare_and_swap_2:
2877   case Builtin::BI__sync_val_compare_and_swap_4:
2878   case Builtin::BI__sync_val_compare_and_swap_8:
2879   case Builtin::BI__sync_val_compare_and_swap_16:
2880     BuiltinIndex = 12;
2881     NumFixed = 2;
2882     break;
2883 
2884   case Builtin::BI__sync_bool_compare_and_swap:
2885   case Builtin::BI__sync_bool_compare_and_swap_1:
2886   case Builtin::BI__sync_bool_compare_and_swap_2:
2887   case Builtin::BI__sync_bool_compare_and_swap_4:
2888   case Builtin::BI__sync_bool_compare_and_swap_8:
2889   case Builtin::BI__sync_bool_compare_and_swap_16:
2890     BuiltinIndex = 13;
2891     NumFixed = 2;
2892     ResultType = Context.BoolTy;
2893     break;
2894 
2895   case Builtin::BI__sync_lock_test_and_set:
2896   case Builtin::BI__sync_lock_test_and_set_1:
2897   case Builtin::BI__sync_lock_test_and_set_2:
2898   case Builtin::BI__sync_lock_test_and_set_4:
2899   case Builtin::BI__sync_lock_test_and_set_8:
2900   case Builtin::BI__sync_lock_test_and_set_16:
2901     BuiltinIndex = 14;
2902     break;
2903 
2904   case Builtin::BI__sync_lock_release:
2905   case Builtin::BI__sync_lock_release_1:
2906   case Builtin::BI__sync_lock_release_2:
2907   case Builtin::BI__sync_lock_release_4:
2908   case Builtin::BI__sync_lock_release_8:
2909   case Builtin::BI__sync_lock_release_16:
2910     BuiltinIndex = 15;
2911     NumFixed = 0;
2912     ResultType = Context.VoidTy;
2913     break;
2914 
2915   case Builtin::BI__sync_swap:
2916   case Builtin::BI__sync_swap_1:
2917   case Builtin::BI__sync_swap_2:
2918   case Builtin::BI__sync_swap_4:
2919   case Builtin::BI__sync_swap_8:
2920   case Builtin::BI__sync_swap_16:
2921     BuiltinIndex = 16;
2922     break;
2923   }
2924 
2925   // Now that we know how many fixed arguments we expect, first check that we
2926   // have at least that many.
2927   if (TheCall->getNumArgs() < 1+NumFixed) {
2928     Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
2929       << 0 << 1+NumFixed << TheCall->getNumArgs()
2930       << TheCall->getCallee()->getSourceRange();
2931     return ExprError();
2932   }
2933 
2934   if (WarnAboutSemanticsChange) {
2935     Diag(TheCall->getLocEnd(), diag::warn_sync_fetch_and_nand_semantics_change)
2936       << TheCall->getCallee()->getSourceRange();
2937   }
2938 
2939   // Get the decl for the concrete builtin from this, we can tell what the
2940   // concrete integer type we should convert to is.
2941   unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
2942   const char *NewBuiltinName = Context.BuiltinInfo.getName(NewBuiltinID);
2943   FunctionDecl *NewBuiltinDecl;
2944   if (NewBuiltinID == BuiltinID)
2945     NewBuiltinDecl = FDecl;
2946   else {
2947     // Perform builtin lookup to avoid redeclaring it.
2948     DeclarationName DN(&Context.Idents.get(NewBuiltinName));
2949     LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
2950     LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
2951     assert(Res.getFoundDecl());
2952     NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
2953     if (!NewBuiltinDecl)
2954       return ExprError();
2955   }
2956 
2957   // The first argument --- the pointer --- has a fixed type; we
2958   // deduce the types of the rest of the arguments accordingly.  Walk
2959   // the remaining arguments, converting them to the deduced value type.
2960   for (unsigned i = 0; i != NumFixed; ++i) {
2961     ExprResult Arg = TheCall->getArg(i+1);
2962 
2963     // GCC does an implicit conversion to the pointer or integer ValType.  This
2964     // can fail in some cases (1i -> int**), check for this error case now.
2965     // Initialize the argument.
2966     InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
2967                                                    ValType, /*consume*/ false);
2968     Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
2969     if (Arg.isInvalid())
2970       return ExprError();
2971 
2972     // Okay, we have something that *can* be converted to the right type.  Check
2973     // to see if there is a potentially weird extension going on here.  This can
2974     // happen when you do an atomic operation on something like an char* and
2975     // pass in 42.  The 42 gets converted to char.  This is even more strange
2976     // for things like 45.123 -> char, etc.
2977     // FIXME: Do this check.
2978     TheCall->setArg(i+1, Arg.get());
2979   }
2980 
2981   ASTContext& Context = this->getASTContext();
2982 
2983   // Create a new DeclRefExpr to refer to the new decl.
2984   DeclRefExpr* NewDRE = DeclRefExpr::Create(
2985       Context,
2986       DRE->getQualifierLoc(),
2987       SourceLocation(),
2988       NewBuiltinDecl,
2989       /*enclosing*/ false,
2990       DRE->getLocation(),
2991       Context.BuiltinFnTy,
2992       DRE->getValueKind());
2993 
2994   // Set the callee in the CallExpr.
2995   // FIXME: This loses syntactic information.
2996   QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
2997   ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
2998                                               CK_BuiltinFnToFnPtr);
2999   TheCall->setCallee(PromotedCall.get());
3000 
3001   // Change the result type of the call to match the original value type. This
3002   // is arbitrary, but the codegen for these builtins ins design to handle it
3003   // gracefully.
3004   TheCall->setType(ResultType);
3005 
3006   return TheCallResult;
3007 }
3008 
3009 /// SemaBuiltinNontemporalOverloaded - We have a call to
3010 /// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an
3011 /// overloaded function based on the pointer type of its last argument.
3012 ///
3013 /// This function goes through and does final semantic checking for these
3014 /// builtins.
SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult)3015 ExprResult Sema::SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult) {
3016   CallExpr *TheCall = (CallExpr *)TheCallResult.get();
3017   DeclRefExpr *DRE =
3018       cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
3019   FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
3020   unsigned BuiltinID = FDecl->getBuiltinID();
3021   assert((BuiltinID == Builtin::BI__builtin_nontemporal_store ||
3022           BuiltinID == Builtin::BI__builtin_nontemporal_load) &&
3023          "Unexpected nontemporal load/store builtin!");
3024   bool isStore = BuiltinID == Builtin::BI__builtin_nontemporal_store;
3025   unsigned numArgs = isStore ? 2 : 1;
3026 
3027   // Ensure that we have the proper number of arguments.
3028   if (checkArgCount(*this, TheCall, numArgs))
3029     return ExprError();
3030 
3031   // Inspect the last argument of the nontemporal builtin.  This should always
3032   // be a pointer type, from which we imply the type of the memory access.
3033   // Because it is a pointer type, we don't have to worry about any implicit
3034   // casts here.
3035   Expr *PointerArg = TheCall->getArg(numArgs - 1);
3036   ExprResult PointerArgResult =
3037       DefaultFunctionArrayLvalueConversion(PointerArg);
3038 
3039   if (PointerArgResult.isInvalid())
3040     return ExprError();
3041   PointerArg = PointerArgResult.get();
3042   TheCall->setArg(numArgs - 1, PointerArg);
3043 
3044   const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>();
3045   if (!pointerType) {
3046     Diag(DRE->getLocStart(), diag::err_nontemporal_builtin_must_be_pointer)
3047         << PointerArg->getType() << PointerArg->getSourceRange();
3048     return ExprError();
3049   }
3050 
3051   QualType ValType = pointerType->getPointeeType();
3052 
3053   // Strip any qualifiers off ValType.
3054   ValType = ValType.getUnqualifiedType();
3055   if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
3056       !ValType->isBlockPointerType() && !ValType->isFloatingType() &&
3057       !ValType->isVectorType()) {
3058     Diag(DRE->getLocStart(),
3059          diag::err_nontemporal_builtin_must_be_pointer_intfltptr_or_vector)
3060         << PointerArg->getType() << PointerArg->getSourceRange();
3061     return ExprError();
3062   }
3063 
3064   if (!isStore) {
3065     TheCall->setType(ValType);
3066     return TheCallResult;
3067   }
3068 
3069   ExprResult ValArg = TheCall->getArg(0);
3070   InitializedEntity Entity = InitializedEntity::InitializeParameter(
3071       Context, ValType, /*consume*/ false);
3072   ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg);
3073   if (ValArg.isInvalid())
3074     return ExprError();
3075 
3076   TheCall->setArg(0, ValArg.get());
3077   TheCall->setType(Context.VoidTy);
3078   return TheCallResult;
3079 }
3080 
3081 /// CheckObjCString - Checks that the argument to the builtin
3082 /// CFString constructor is correct
3083 /// Note: It might also make sense to do the UTF-16 conversion here (would
3084 /// simplify the backend).
CheckObjCString(Expr * Arg)3085 bool Sema::CheckObjCString(Expr *Arg) {
3086   Arg = Arg->IgnoreParenCasts();
3087   StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
3088 
3089   if (!Literal || !Literal->isAscii()) {
3090     Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
3091       << Arg->getSourceRange();
3092     return true;
3093   }
3094 
3095   if (Literal->containsNonAsciiOrNull()) {
3096     StringRef String = Literal->getString();
3097     unsigned NumBytes = String.size();
3098     SmallVector<UTF16, 128> ToBuf(NumBytes);
3099     const UTF8 *FromPtr = (const UTF8 *)String.data();
3100     UTF16 *ToPtr = &ToBuf[0];
3101 
3102     ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
3103                                                  &ToPtr, ToPtr + NumBytes,
3104                                                  strictConversion);
3105     // Check for conversion failure.
3106     if (Result != conversionOK)
3107       Diag(Arg->getLocStart(),
3108            diag::warn_cfstring_truncated) << Arg->getSourceRange();
3109   }
3110   return false;
3111 }
3112 
3113 /// Check the arguments to '__builtin_va_start' or '__builtin_ms_va_start'
3114 /// for validity.  Emit an error and return true on failure; return false
3115 /// on success.
SemaBuiltinVAStartImpl(CallExpr * TheCall)3116 bool Sema::SemaBuiltinVAStartImpl(CallExpr *TheCall) {
3117   Expr *Fn = TheCall->getCallee();
3118   if (TheCall->getNumArgs() > 2) {
3119     Diag(TheCall->getArg(2)->getLocStart(),
3120          diag::err_typecheck_call_too_many_args)
3121       << 0 /*function call*/ << 2 << TheCall->getNumArgs()
3122       << Fn->getSourceRange()
3123       << SourceRange(TheCall->getArg(2)->getLocStart(),
3124                      (*(TheCall->arg_end()-1))->getLocEnd());
3125     return true;
3126   }
3127 
3128   if (TheCall->getNumArgs() < 2) {
3129     return Diag(TheCall->getLocEnd(),
3130       diag::err_typecheck_call_too_few_args_at_least)
3131       << 0 /*function call*/ << 2 << TheCall->getNumArgs();
3132   }
3133 
3134   // Type-check the first argument normally.
3135   if (checkBuiltinArgument(*this, TheCall, 0))
3136     return true;
3137 
3138   // Determine whether the current function is variadic or not.
3139   BlockScopeInfo *CurBlock = getCurBlock();
3140   bool isVariadic;
3141   if (CurBlock)
3142     isVariadic = CurBlock->TheDecl->isVariadic();
3143   else if (FunctionDecl *FD = getCurFunctionDecl())
3144     isVariadic = FD->isVariadic();
3145   else
3146     isVariadic = getCurMethodDecl()->isVariadic();
3147 
3148   if (!isVariadic) {
3149     Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
3150     return true;
3151   }
3152 
3153   // Verify that the second argument to the builtin is the last argument of the
3154   // current function or method.
3155   bool SecondArgIsLastNamedArgument = false;
3156   const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
3157 
3158   // These are valid if SecondArgIsLastNamedArgument is false after the next
3159   // block.
3160   QualType Type;
3161   SourceLocation ParamLoc;
3162   bool IsCRegister = false;
3163 
3164   if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
3165     if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
3166       // FIXME: This isn't correct for methods (results in bogus warning).
3167       // Get the last formal in the current function.
3168       const ParmVarDecl *LastArg;
3169       if (CurBlock)
3170         LastArg = CurBlock->TheDecl->parameters().back();
3171       else if (FunctionDecl *FD = getCurFunctionDecl())
3172         LastArg = FD->parameters().back();
3173       else
3174         LastArg = getCurMethodDecl()->parameters().back();
3175       SecondArgIsLastNamedArgument = PV == LastArg;
3176 
3177       Type = PV->getType();
3178       ParamLoc = PV->getLocation();
3179       IsCRegister =
3180           PV->getStorageClass() == SC_Register && !getLangOpts().CPlusPlus;
3181     }
3182   }
3183 
3184   if (!SecondArgIsLastNamedArgument)
3185     Diag(TheCall->getArg(1)->getLocStart(),
3186          diag::warn_second_arg_of_va_start_not_last_named_param);
3187   else if (IsCRegister || Type->isReferenceType() ||
3188            Type->isPromotableIntegerType() ||
3189            Type->isSpecificBuiltinType(BuiltinType::Float)) {
3190     unsigned Reason = 0;
3191     if (Type->isReferenceType())  Reason = 1;
3192     else if (IsCRegister)         Reason = 2;
3193     Diag(Arg->getLocStart(), diag::warn_va_start_type_is_undefined) << Reason;
3194     Diag(ParamLoc, diag::note_parameter_type) << Type;
3195   }
3196 
3197   TheCall->setType(Context.VoidTy);
3198   return false;
3199 }
3200 
3201 /// Check the arguments to '__builtin_va_start' for validity, and that
3202 /// it was called from a function of the native ABI.
3203 /// Emit an error and return true on failure; return false on success.
SemaBuiltinVAStart(CallExpr * TheCall)3204 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
3205   // On x86-64 Unix, don't allow this in Win64 ABI functions.
3206   // On x64 Windows, don't allow this in System V ABI functions.
3207   // (Yes, that means there's no corresponding way to support variadic
3208   // System V ABI functions on Windows.)
3209   if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86_64) {
3210     unsigned OS = Context.getTargetInfo().getTriple().getOS();
3211     clang::CallingConv CC = CC_C;
3212     if (const FunctionDecl *FD = getCurFunctionDecl())
3213       CC = FD->getType()->getAs<FunctionType>()->getCallConv();
3214     if ((OS == llvm::Triple::Win32 && CC == CC_X86_64SysV) ||
3215         (OS != llvm::Triple::Win32 && CC == CC_X86_64Win64))
3216       return Diag(TheCall->getCallee()->getLocStart(),
3217                   diag::err_va_start_used_in_wrong_abi_function)
3218              << (OS != llvm::Triple::Win32);
3219   }
3220   return SemaBuiltinVAStartImpl(TheCall);
3221 }
3222 
3223 /// Check the arguments to '__builtin_ms_va_start' for validity, and that
3224 /// it was called from a Win64 ABI function.
3225 /// Emit an error and return true on failure; return false on success.
SemaBuiltinMSVAStart(CallExpr * TheCall)3226 bool Sema::SemaBuiltinMSVAStart(CallExpr *TheCall) {
3227   // This only makes sense for x86-64.
3228   const llvm::Triple &TT = Context.getTargetInfo().getTriple();
3229   Expr *Callee = TheCall->getCallee();
3230   if (TT.getArch() != llvm::Triple::x86_64)
3231     return Diag(Callee->getLocStart(), diag::err_x86_builtin_32_bit_tgt);
3232   // Don't allow this in System V ABI functions.
3233   clang::CallingConv CC = CC_C;
3234   if (const FunctionDecl *FD = getCurFunctionDecl())
3235     CC = FD->getType()->getAs<FunctionType>()->getCallConv();
3236   if (CC == CC_X86_64SysV ||
3237       (TT.getOS() != llvm::Triple::Win32 && CC != CC_X86_64Win64))
3238     return Diag(Callee->getLocStart(),
3239                 diag::err_ms_va_start_used_in_sysv_function);
3240   return SemaBuiltinVAStartImpl(TheCall);
3241 }
3242 
SemaBuiltinVAStartARM(CallExpr * Call)3243 bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) {
3244   // void __va_start(va_list *ap, const char *named_addr, size_t slot_size,
3245   //                 const char *named_addr);
3246 
3247   Expr *Func = Call->getCallee();
3248 
3249   if (Call->getNumArgs() < 3)
3250     return Diag(Call->getLocEnd(),
3251                 diag::err_typecheck_call_too_few_args_at_least)
3252            << 0 /*function call*/ << 3 << Call->getNumArgs();
3253 
3254   // Determine whether the current function is variadic or not.
3255   bool IsVariadic;
3256   if (BlockScopeInfo *CurBlock = getCurBlock())
3257     IsVariadic = CurBlock->TheDecl->isVariadic();
3258   else if (FunctionDecl *FD = getCurFunctionDecl())
3259     IsVariadic = FD->isVariadic();
3260   else if (ObjCMethodDecl *MD = getCurMethodDecl())
3261     IsVariadic = MD->isVariadic();
3262   else
3263     llvm_unreachable("unexpected statement type");
3264 
3265   if (!IsVariadic) {
3266     Diag(Func->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
3267     return true;
3268   }
3269 
3270   // Type-check the first argument normally.
3271   if (checkBuiltinArgument(*this, Call, 0))
3272     return true;
3273 
3274   const struct {
3275     unsigned ArgNo;
3276     QualType Type;
3277   } ArgumentTypes[] = {
3278     { 1, Context.getPointerType(Context.CharTy.withConst()) },
3279     { 2, Context.getSizeType() },
3280   };
3281 
3282   for (const auto &AT : ArgumentTypes) {
3283     const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens();
3284     if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType())
3285       continue;
3286     Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible)
3287       << Arg->getType() << AT.Type << 1 /* different class */
3288       << 0 /* qualifier difference */ << 3 /* parameter mismatch */
3289       << AT.ArgNo + 1 << Arg->getType() << AT.Type;
3290   }
3291 
3292   return false;
3293 }
3294 
3295 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
3296 /// friends.  This is declared to take (...), so we have to check everything.
SemaBuiltinUnorderedCompare(CallExpr * TheCall)3297 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
3298   if (TheCall->getNumArgs() < 2)
3299     return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
3300       << 0 << 2 << TheCall->getNumArgs()/*function call*/;
3301   if (TheCall->getNumArgs() > 2)
3302     return Diag(TheCall->getArg(2)->getLocStart(),
3303                 diag::err_typecheck_call_too_many_args)
3304       << 0 /*function call*/ << 2 << TheCall->getNumArgs()
3305       << SourceRange(TheCall->getArg(2)->getLocStart(),
3306                      (*(TheCall->arg_end()-1))->getLocEnd());
3307 
3308   ExprResult OrigArg0 = TheCall->getArg(0);
3309   ExprResult OrigArg1 = TheCall->getArg(1);
3310 
3311   // Do standard promotions between the two arguments, returning their common
3312   // type.
3313   QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
3314   if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
3315     return true;
3316 
3317   // Make sure any conversions are pushed back into the call; this is
3318   // type safe since unordered compare builtins are declared as "_Bool
3319   // foo(...)".
3320   TheCall->setArg(0, OrigArg0.get());
3321   TheCall->setArg(1, OrigArg1.get());
3322 
3323   if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
3324     return false;
3325 
3326   // If the common type isn't a real floating type, then the arguments were
3327   // invalid for this operation.
3328   if (Res.isNull() || !Res->isRealFloatingType())
3329     return Diag(OrigArg0.get()->getLocStart(),
3330                 diag::err_typecheck_call_invalid_ordered_compare)
3331       << OrigArg0.get()->getType() << OrigArg1.get()->getType()
3332       << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
3333 
3334   return false;
3335 }
3336 
3337 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
3338 /// __builtin_isnan and friends.  This is declared to take (...), so we have
3339 /// to check everything. We expect the last argument to be a floating point
3340 /// value.
SemaBuiltinFPClassification(CallExpr * TheCall,unsigned NumArgs)3341 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
3342   if (TheCall->getNumArgs() < NumArgs)
3343     return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
3344       << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
3345   if (TheCall->getNumArgs() > NumArgs)
3346     return Diag(TheCall->getArg(NumArgs)->getLocStart(),
3347                 diag::err_typecheck_call_too_many_args)
3348       << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
3349       << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
3350                      (*(TheCall->arg_end()-1))->getLocEnd());
3351 
3352   Expr *OrigArg = TheCall->getArg(NumArgs-1);
3353 
3354   if (OrigArg->isTypeDependent())
3355     return false;
3356 
3357   // This operation requires a non-_Complex floating-point number.
3358   if (!OrigArg->getType()->isRealFloatingType())
3359     return Diag(OrigArg->getLocStart(),
3360                 diag::err_typecheck_call_invalid_unary_fp)
3361       << OrigArg->getType() << OrigArg->getSourceRange();
3362 
3363   // If this is an implicit conversion from float -> double, remove it.
3364   if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
3365     Expr *CastArg = Cast->getSubExpr();
3366     if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
3367       assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
3368              "promotion from float to double is the only expected cast here");
3369       Cast->setSubExpr(nullptr);
3370       TheCall->setArg(NumArgs-1, CastArg);
3371     }
3372   }
3373 
3374   return false;
3375 }
3376 
3377 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
3378 // This is declared to take (...), so we have to check everything.
SemaBuiltinShuffleVector(CallExpr * TheCall)3379 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
3380   if (TheCall->getNumArgs() < 2)
3381     return ExprError(Diag(TheCall->getLocEnd(),
3382                           diag::err_typecheck_call_too_few_args_at_least)
3383                      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
3384                      << TheCall->getSourceRange());
3385 
3386   // Determine which of the following types of shufflevector we're checking:
3387   // 1) unary, vector mask: (lhs, mask)
3388   // 2) binary, scalar mask: (lhs, rhs, index, ..., index)
3389   QualType resType = TheCall->getArg(0)->getType();
3390   unsigned numElements = 0;
3391 
3392   if (!TheCall->getArg(0)->isTypeDependent() &&
3393       !TheCall->getArg(1)->isTypeDependent()) {
3394     QualType LHSType = TheCall->getArg(0)->getType();
3395     QualType RHSType = TheCall->getArg(1)->getType();
3396 
3397     if (!LHSType->isVectorType() || !RHSType->isVectorType())
3398       return ExprError(Diag(TheCall->getLocStart(),
3399                             diag::err_shufflevector_non_vector)
3400                        << SourceRange(TheCall->getArg(0)->getLocStart(),
3401                                       TheCall->getArg(1)->getLocEnd()));
3402 
3403     numElements = LHSType->getAs<VectorType>()->getNumElements();
3404     unsigned numResElements = TheCall->getNumArgs() - 2;
3405 
3406     // Check to see if we have a call with 2 vector arguments, the unary shuffle
3407     // with mask.  If so, verify that RHS is an integer vector type with the
3408     // same number of elts as lhs.
3409     if (TheCall->getNumArgs() == 2) {
3410       if (!RHSType->hasIntegerRepresentation() ||
3411           RHSType->getAs<VectorType>()->getNumElements() != numElements)
3412         return ExprError(Diag(TheCall->getLocStart(),
3413                               diag::err_shufflevector_incompatible_vector)
3414                          << SourceRange(TheCall->getArg(1)->getLocStart(),
3415                                         TheCall->getArg(1)->getLocEnd()));
3416     } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
3417       return ExprError(Diag(TheCall->getLocStart(),
3418                             diag::err_shufflevector_incompatible_vector)
3419                        << SourceRange(TheCall->getArg(0)->getLocStart(),
3420                                       TheCall->getArg(1)->getLocEnd()));
3421     } else if (numElements != numResElements) {
3422       QualType eltType = LHSType->getAs<VectorType>()->getElementType();
3423       resType = Context.getVectorType(eltType, numResElements,
3424                                       VectorType::GenericVector);
3425     }
3426   }
3427 
3428   for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
3429     if (TheCall->getArg(i)->isTypeDependent() ||
3430         TheCall->getArg(i)->isValueDependent())
3431       continue;
3432 
3433     llvm::APSInt Result(32);
3434     if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
3435       return ExprError(Diag(TheCall->getLocStart(),
3436                             diag::err_shufflevector_nonconstant_argument)
3437                        << TheCall->getArg(i)->getSourceRange());
3438 
3439     // Allow -1 which will be translated to undef in the IR.
3440     if (Result.isSigned() && Result.isAllOnesValue())
3441       continue;
3442 
3443     if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
3444       return ExprError(Diag(TheCall->getLocStart(),
3445                             diag::err_shufflevector_argument_too_large)
3446                        << TheCall->getArg(i)->getSourceRange());
3447   }
3448 
3449   SmallVector<Expr*, 32> exprs;
3450 
3451   for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
3452     exprs.push_back(TheCall->getArg(i));
3453     TheCall->setArg(i, nullptr);
3454   }
3455 
3456   return new (Context) ShuffleVectorExpr(Context, exprs, resType,
3457                                          TheCall->getCallee()->getLocStart(),
3458                                          TheCall->getRParenLoc());
3459 }
3460 
3461 /// SemaConvertVectorExpr - Handle __builtin_convertvector
SemaConvertVectorExpr(Expr * E,TypeSourceInfo * TInfo,SourceLocation BuiltinLoc,SourceLocation RParenLoc)3462 ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
3463                                        SourceLocation BuiltinLoc,
3464                                        SourceLocation RParenLoc) {
3465   ExprValueKind VK = VK_RValue;
3466   ExprObjectKind OK = OK_Ordinary;
3467   QualType DstTy = TInfo->getType();
3468   QualType SrcTy = E->getType();
3469 
3470   if (!SrcTy->isVectorType() && !SrcTy->isDependentType())
3471     return ExprError(Diag(BuiltinLoc,
3472                           diag::err_convertvector_non_vector)
3473                      << E->getSourceRange());
3474   if (!DstTy->isVectorType() && !DstTy->isDependentType())
3475     return ExprError(Diag(BuiltinLoc,
3476                           diag::err_convertvector_non_vector_type));
3477 
3478   if (!SrcTy->isDependentType() && !DstTy->isDependentType()) {
3479     unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements();
3480     unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements();
3481     if (SrcElts != DstElts)
3482       return ExprError(Diag(BuiltinLoc,
3483                             diag::err_convertvector_incompatible_vector)
3484                        << E->getSourceRange());
3485   }
3486 
3487   return new (Context)
3488       ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc);
3489 }
3490 
3491 /// SemaBuiltinPrefetch - Handle __builtin_prefetch.
3492 // This is declared to take (const void*, ...) and can take two
3493 // optional constant int args.
SemaBuiltinPrefetch(CallExpr * TheCall)3494 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
3495   unsigned NumArgs = TheCall->getNumArgs();
3496 
3497   if (NumArgs > 3)
3498     return Diag(TheCall->getLocEnd(),
3499              diag::err_typecheck_call_too_many_args_at_most)
3500              << 0 /*function call*/ << 3 << NumArgs
3501              << TheCall->getSourceRange();
3502 
3503   // Argument 0 is checked for us and the remaining arguments must be
3504   // constant integers.
3505   for (unsigned i = 1; i != NumArgs; ++i)
3506     if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3))
3507       return true;
3508 
3509   return false;
3510 }
3511 
3512 /// SemaBuiltinAssume - Handle __assume (MS Extension).
3513 // __assume does not evaluate its arguments, and should warn if its argument
3514 // has side effects.
SemaBuiltinAssume(CallExpr * TheCall)3515 bool Sema::SemaBuiltinAssume(CallExpr *TheCall) {
3516   Expr *Arg = TheCall->getArg(0);
3517   if (Arg->isInstantiationDependent()) return false;
3518 
3519   if (Arg->HasSideEffects(Context))
3520     Diag(Arg->getLocStart(), diag::warn_assume_side_effects)
3521       << Arg->getSourceRange()
3522       << cast<FunctionDecl>(TheCall->getCalleeDecl())->getIdentifier();
3523 
3524   return false;
3525 }
3526 
3527 /// Handle __builtin_assume_aligned. This is declared
3528 /// as (const void*, size_t, ...) and can take one optional constant int arg.
SemaBuiltinAssumeAligned(CallExpr * TheCall)3529 bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) {
3530   unsigned NumArgs = TheCall->getNumArgs();
3531 
3532   if (NumArgs > 3)
3533     return Diag(TheCall->getLocEnd(),
3534              diag::err_typecheck_call_too_many_args_at_most)
3535              << 0 /*function call*/ << 3 << NumArgs
3536              << TheCall->getSourceRange();
3537 
3538   // The alignment must be a constant integer.
3539   Expr *Arg = TheCall->getArg(1);
3540 
3541   // We can't check the value of a dependent argument.
3542   if (!Arg->isTypeDependent() && !Arg->isValueDependent()) {
3543     llvm::APSInt Result;
3544     if (SemaBuiltinConstantArg(TheCall, 1, Result))
3545       return true;
3546 
3547     if (!Result.isPowerOf2())
3548       return Diag(TheCall->getLocStart(),
3549                   diag::err_alignment_not_power_of_two)
3550            << Arg->getSourceRange();
3551   }
3552 
3553   if (NumArgs > 2) {
3554     ExprResult Arg(TheCall->getArg(2));
3555     InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
3556       Context.getSizeType(), false);
3557     Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
3558     if (Arg.isInvalid()) return true;
3559     TheCall->setArg(2, Arg.get());
3560   }
3561 
3562   return false;
3563 }
3564 
3565 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
3566 /// TheCall is a constant expression.
SemaBuiltinConstantArg(CallExpr * TheCall,int ArgNum,llvm::APSInt & Result)3567 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
3568                                   llvm::APSInt &Result) {
3569   Expr *Arg = TheCall->getArg(ArgNum);
3570   DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
3571   FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
3572 
3573   if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
3574 
3575   if (!Arg->isIntegerConstantExpr(Result, Context))
3576     return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
3577                 << FDecl->getDeclName() <<  Arg->getSourceRange();
3578 
3579   return false;
3580 }
3581 
3582 /// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
3583 /// TheCall is a constant expression in the range [Low, High].
SemaBuiltinConstantArgRange(CallExpr * TheCall,int ArgNum,int Low,int High)3584 bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum,
3585                                        int Low, int High) {
3586   llvm::APSInt Result;
3587 
3588   // We can't check the value of a dependent argument.
3589   Expr *Arg = TheCall->getArg(ArgNum);
3590   if (Arg->isTypeDependent() || Arg->isValueDependent())
3591     return false;
3592 
3593   // Check constant-ness first.
3594   if (SemaBuiltinConstantArg(TheCall, ArgNum, Result))
3595     return true;
3596 
3597   if (Result.getSExtValue() < Low || Result.getSExtValue() > High)
3598     return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
3599       << Low << High << Arg->getSourceRange();
3600 
3601   return false;
3602 }
3603 
3604 /// SemaBuiltinARMSpecialReg - Handle a check if argument ArgNum of CallExpr
3605 /// TheCall is an ARM/AArch64 special register string literal.
SemaBuiltinARMSpecialReg(unsigned BuiltinID,CallExpr * TheCall,int ArgNum,unsigned ExpectedFieldNum,bool AllowName)3606 bool Sema::SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
3607                                     int ArgNum, unsigned ExpectedFieldNum,
3608                                     bool AllowName) {
3609   bool IsARMBuiltin = BuiltinID == ARM::BI__builtin_arm_rsr64 ||
3610                       BuiltinID == ARM::BI__builtin_arm_wsr64 ||
3611                       BuiltinID == ARM::BI__builtin_arm_rsr ||
3612                       BuiltinID == ARM::BI__builtin_arm_rsrp ||
3613                       BuiltinID == ARM::BI__builtin_arm_wsr ||
3614                       BuiltinID == ARM::BI__builtin_arm_wsrp;
3615   bool IsAArch64Builtin = BuiltinID == AArch64::BI__builtin_arm_rsr64 ||
3616                           BuiltinID == AArch64::BI__builtin_arm_wsr64 ||
3617                           BuiltinID == AArch64::BI__builtin_arm_rsr ||
3618                           BuiltinID == AArch64::BI__builtin_arm_rsrp ||
3619                           BuiltinID == AArch64::BI__builtin_arm_wsr ||
3620                           BuiltinID == AArch64::BI__builtin_arm_wsrp;
3621   assert((IsARMBuiltin || IsAArch64Builtin) && "Unexpected ARM builtin.");
3622 
3623   // We can't check the value of a dependent argument.
3624   Expr *Arg = TheCall->getArg(ArgNum);
3625   if (Arg->isTypeDependent() || Arg->isValueDependent())
3626     return false;
3627 
3628   // Check if the argument is a string literal.
3629   if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts()))
3630     return Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal)
3631            << Arg->getSourceRange();
3632 
3633   // Check the type of special register given.
3634   StringRef Reg = cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString();
3635   SmallVector<StringRef, 6> Fields;
3636   Reg.split(Fields, ":");
3637 
3638   if (Fields.size() != ExpectedFieldNum && !(AllowName && Fields.size() == 1))
3639     return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg)
3640            << Arg->getSourceRange();
3641 
3642   // If the string is the name of a register then we cannot check that it is
3643   // valid here but if the string is of one the forms described in ACLE then we
3644   // can check that the supplied fields are integers and within the valid
3645   // ranges.
3646   if (Fields.size() > 1) {
3647     bool FiveFields = Fields.size() == 5;
3648 
3649     bool ValidString = true;
3650     if (IsARMBuiltin) {
3651       ValidString &= Fields[0].startswith_lower("cp") ||
3652                      Fields[0].startswith_lower("p");
3653       if (ValidString)
3654         Fields[0] =
3655           Fields[0].drop_front(Fields[0].startswith_lower("cp") ? 2 : 1);
3656 
3657       ValidString &= Fields[2].startswith_lower("c");
3658       if (ValidString)
3659         Fields[2] = Fields[2].drop_front(1);
3660 
3661       if (FiveFields) {
3662         ValidString &= Fields[3].startswith_lower("c");
3663         if (ValidString)
3664           Fields[3] = Fields[3].drop_front(1);
3665       }
3666     }
3667 
3668     SmallVector<int, 5> Ranges;
3669     if (FiveFields)
3670       Ranges.append({IsAArch64Builtin ? 1 : 15, 7, 7, 15, 15});
3671     else
3672       Ranges.append({15, 7, 15});
3673 
3674     for (unsigned i=0; i<Fields.size(); ++i) {
3675       int IntField;
3676       ValidString &= !Fields[i].getAsInteger(10, IntField);
3677       ValidString &= (IntField >= 0 && IntField <= Ranges[i]);
3678     }
3679 
3680     if (!ValidString)
3681       return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg)
3682              << Arg->getSourceRange();
3683 
3684   } else if (IsAArch64Builtin && Fields.size() == 1) {
3685     // If the register name is one of those that appear in the condition below
3686     // and the special register builtin being used is one of the write builtins,
3687     // then we require that the argument provided for writing to the register
3688     // is an integer constant expression. This is because it will be lowered to
3689     // an MSR (immediate) instruction, so we need to know the immediate at
3690     // compile time.
3691     if (TheCall->getNumArgs() != 2)
3692       return false;
3693 
3694     std::string RegLower = Reg.lower();
3695     if (RegLower != "spsel" && RegLower != "daifset" && RegLower != "daifclr" &&
3696         RegLower != "pan" && RegLower != "uao")
3697       return false;
3698 
3699     return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15);
3700   }
3701 
3702   return false;
3703 }
3704 
3705 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
3706 /// This checks that the target supports __builtin_longjmp and
3707 /// that val is a constant 1.
SemaBuiltinLongjmp(CallExpr * TheCall)3708 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
3709   if (!Context.getTargetInfo().hasSjLjLowering())
3710     return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_unsupported)
3711              << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd());
3712 
3713   Expr *Arg = TheCall->getArg(1);
3714   llvm::APSInt Result;
3715 
3716   // TODO: This is less than ideal. Overload this to take a value.
3717   if (SemaBuiltinConstantArg(TheCall, 1, Result))
3718     return true;
3719 
3720   if (Result != 1)
3721     return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
3722              << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
3723 
3724   return false;
3725 }
3726 
3727 /// SemaBuiltinSetjmp - Handle __builtin_setjmp(void *env[5]).
3728 /// This checks that the target supports __builtin_setjmp.
SemaBuiltinSetjmp(CallExpr * TheCall)3729 bool Sema::SemaBuiltinSetjmp(CallExpr *TheCall) {
3730   if (!Context.getTargetInfo().hasSjLjLowering())
3731     return Diag(TheCall->getLocStart(), diag::err_builtin_setjmp_unsupported)
3732              << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd());
3733   return false;
3734 }
3735 
3736 namespace {
3737 class UncoveredArgHandler {
3738   enum { Unknown = -1, AllCovered = -2 };
3739   signed FirstUncoveredArg;
3740   SmallVector<const Expr *, 4> DiagnosticExprs;
3741 
3742 public:
UncoveredArgHandler()3743   UncoveredArgHandler() : FirstUncoveredArg(Unknown) { }
3744 
hasUncoveredArg() const3745   bool hasUncoveredArg() const {
3746     return (FirstUncoveredArg >= 0);
3747   }
3748 
getUncoveredArg() const3749   unsigned getUncoveredArg() const {
3750     assert(hasUncoveredArg() && "no uncovered argument");
3751     return FirstUncoveredArg;
3752   }
3753 
setAllCovered()3754   void setAllCovered() {
3755     // A string has been found with all arguments covered, so clear out
3756     // the diagnostics.
3757     DiagnosticExprs.clear();
3758     FirstUncoveredArg = AllCovered;
3759   }
3760 
Update(signed NewFirstUncoveredArg,const Expr * StrExpr)3761   void Update(signed NewFirstUncoveredArg, const Expr *StrExpr) {
3762     assert(NewFirstUncoveredArg >= 0 && "Outside range");
3763 
3764     // Don't update if a previous string covers all arguments.
3765     if (FirstUncoveredArg == AllCovered)
3766       return;
3767 
3768     // UncoveredArgHandler tracks the highest uncovered argument index
3769     // and with it all the strings that match this index.
3770     if (NewFirstUncoveredArg == FirstUncoveredArg)
3771       DiagnosticExprs.push_back(StrExpr);
3772     else if (NewFirstUncoveredArg > FirstUncoveredArg) {
3773       DiagnosticExprs.clear();
3774       DiagnosticExprs.push_back(StrExpr);
3775       FirstUncoveredArg = NewFirstUncoveredArg;
3776     }
3777   }
3778 
3779   void Diagnose(Sema &S, bool IsFunctionCall, const Expr *ArgExpr);
3780 };
3781 
3782 enum StringLiteralCheckType {
3783   SLCT_NotALiteral,
3784   SLCT_UncheckedLiteral,
3785   SLCT_CheckedLiteral
3786 };
3787 } // end anonymous namespace
3788 
3789 static void CheckFormatString(Sema &S, const StringLiteral *FExpr,
3790                               const Expr *OrigFormatExpr,
3791                               ArrayRef<const Expr *> Args,
3792                               bool HasVAListArg, unsigned format_idx,
3793                               unsigned firstDataArg,
3794                               Sema::FormatStringType Type,
3795                               bool inFunctionCall,
3796                               Sema::VariadicCallType CallType,
3797                               llvm::SmallBitVector &CheckedVarArgs,
3798                               UncoveredArgHandler &UncoveredArg);
3799 
3800 // Determine if an expression is a string literal or constant string.
3801 // If this function returns false on the arguments to a function expecting a
3802 // format string, we will usually need to emit a warning.
3803 // True string literals are then checked by CheckFormatString.
3804 static StringLiteralCheckType
checkFormatStringExpr(Sema & S,const Expr * E,ArrayRef<const Expr * > Args,bool HasVAListArg,unsigned format_idx,unsigned firstDataArg,Sema::FormatStringType Type,Sema::VariadicCallType CallType,bool InFunctionCall,llvm::SmallBitVector & CheckedVarArgs,UncoveredArgHandler & UncoveredArg)3805 checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args,
3806                       bool HasVAListArg, unsigned format_idx,
3807                       unsigned firstDataArg, Sema::FormatStringType Type,
3808                       Sema::VariadicCallType CallType, bool InFunctionCall,
3809                       llvm::SmallBitVector &CheckedVarArgs,
3810                       UncoveredArgHandler &UncoveredArg) {
3811  tryAgain:
3812   if (E->isTypeDependent() || E->isValueDependent())
3813     return SLCT_NotALiteral;
3814 
3815   E = E->IgnoreParenCasts();
3816 
3817   if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull))
3818     // Technically -Wformat-nonliteral does not warn about this case.
3819     // The behavior of printf and friends in this case is implementation
3820     // dependent.  Ideally if the format string cannot be null then
3821     // it should have a 'nonnull' attribute in the function prototype.
3822     return SLCT_UncheckedLiteral;
3823 
3824   switch (E->getStmtClass()) {
3825   case Stmt::BinaryConditionalOperatorClass:
3826   case Stmt::ConditionalOperatorClass: {
3827     // The expression is a literal if both sub-expressions were, and it was
3828     // completely checked only if both sub-expressions were checked.
3829     const AbstractConditionalOperator *C =
3830         cast<AbstractConditionalOperator>(E);
3831 
3832     // Determine whether it is necessary to check both sub-expressions, for
3833     // example, because the condition expression is a constant that can be
3834     // evaluated at compile time.
3835     bool CheckLeft = true, CheckRight = true;
3836 
3837     bool Cond;
3838     if (C->getCond()->EvaluateAsBooleanCondition(Cond, S.getASTContext())) {
3839       if (Cond)
3840         CheckRight = false;
3841       else
3842         CheckLeft = false;
3843     }
3844 
3845     StringLiteralCheckType Left;
3846     if (!CheckLeft)
3847       Left = SLCT_UncheckedLiteral;
3848     else {
3849       Left = checkFormatStringExpr(S, C->getTrueExpr(), Args,
3850                                    HasVAListArg, format_idx, firstDataArg,
3851                                    Type, CallType, InFunctionCall,
3852                                    CheckedVarArgs, UncoveredArg);
3853       if (Left == SLCT_NotALiteral || !CheckRight)
3854         return Left;
3855     }
3856 
3857     StringLiteralCheckType Right =
3858         checkFormatStringExpr(S, C->getFalseExpr(), Args,
3859                               HasVAListArg, format_idx, firstDataArg,
3860                               Type, CallType, InFunctionCall, CheckedVarArgs,
3861                               UncoveredArg);
3862 
3863     return (CheckLeft && Left < Right) ? Left : Right;
3864   }
3865 
3866   case Stmt::ImplicitCastExprClass: {
3867     E = cast<ImplicitCastExpr>(E)->getSubExpr();
3868     goto tryAgain;
3869   }
3870 
3871   case Stmt::OpaqueValueExprClass:
3872     if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
3873       E = src;
3874       goto tryAgain;
3875     }
3876     return SLCT_NotALiteral;
3877 
3878   case Stmt::PredefinedExprClass:
3879     // While __func__, etc., are technically not string literals, they
3880     // cannot contain format specifiers and thus are not a security
3881     // liability.
3882     return SLCT_UncheckedLiteral;
3883 
3884   case Stmt::DeclRefExprClass: {
3885     const DeclRefExpr *DR = cast<DeclRefExpr>(E);
3886 
3887     // As an exception, do not flag errors for variables binding to
3888     // const string literals.
3889     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
3890       bool isConstant = false;
3891       QualType T = DR->getType();
3892 
3893       if (const ArrayType *AT = S.Context.getAsArrayType(T)) {
3894         isConstant = AT->getElementType().isConstant(S.Context);
3895       } else if (const PointerType *PT = T->getAs<PointerType>()) {
3896         isConstant = T.isConstant(S.Context) &&
3897                      PT->getPointeeType().isConstant(S.Context);
3898       } else if (T->isObjCObjectPointerType()) {
3899         // In ObjC, there is usually no "const ObjectPointer" type,
3900         // so don't check if the pointee type is constant.
3901         isConstant = T.isConstant(S.Context);
3902       }
3903 
3904       if (isConstant) {
3905         if (const Expr *Init = VD->getAnyInitializer()) {
3906           // Look through initializers like const char c[] = { "foo" }
3907           if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
3908             if (InitList->isStringLiteralInit())
3909               Init = InitList->getInit(0)->IgnoreParenImpCasts();
3910           }
3911           return checkFormatStringExpr(S, Init, Args,
3912                                        HasVAListArg, format_idx,
3913                                        firstDataArg, Type, CallType,
3914                                        /*InFunctionCall*/false, CheckedVarArgs,
3915                                        UncoveredArg);
3916         }
3917       }
3918 
3919       // For vprintf* functions (i.e., HasVAListArg==true), we add a
3920       // special check to see if the format string is a function parameter
3921       // of the function calling the printf function.  If the function
3922       // has an attribute indicating it is a printf-like function, then we
3923       // should suppress warnings concerning non-literals being used in a call
3924       // to a vprintf function.  For example:
3925       //
3926       // void
3927       // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
3928       //      va_list ap;
3929       //      va_start(ap, fmt);
3930       //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
3931       //      ...
3932       // }
3933       if (HasVAListArg) {
3934         if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
3935           if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
3936             int PVIndex = PV->getFunctionScopeIndex() + 1;
3937             for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) {
3938               // adjust for implicit parameter
3939               if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
3940                 if (MD->isInstance())
3941                   ++PVIndex;
3942               // We also check if the formats are compatible.
3943               // We can't pass a 'scanf' string to a 'printf' function.
3944               if (PVIndex == PVFormat->getFormatIdx() &&
3945                   Type == S.GetFormatStringType(PVFormat))
3946                 return SLCT_UncheckedLiteral;
3947             }
3948           }
3949         }
3950       }
3951     }
3952 
3953     return SLCT_NotALiteral;
3954   }
3955 
3956   case Stmt::CallExprClass:
3957   case Stmt::CXXMemberCallExprClass: {
3958     const CallExpr *CE = cast<CallExpr>(E);
3959     if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
3960       if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
3961         unsigned ArgIndex = FA->getFormatIdx();
3962         if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
3963           if (MD->isInstance())
3964             --ArgIndex;
3965         const Expr *Arg = CE->getArg(ArgIndex - 1);
3966 
3967         return checkFormatStringExpr(S, Arg, Args,
3968                                      HasVAListArg, format_idx, firstDataArg,
3969                                      Type, CallType, InFunctionCall,
3970                                      CheckedVarArgs, UncoveredArg);
3971       } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
3972         unsigned BuiltinID = FD->getBuiltinID();
3973         if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
3974             BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
3975           const Expr *Arg = CE->getArg(0);
3976           return checkFormatStringExpr(S, Arg, Args,
3977                                        HasVAListArg, format_idx,
3978                                        firstDataArg, Type, CallType,
3979                                        InFunctionCall, CheckedVarArgs,
3980                                        UncoveredArg);
3981         }
3982       }
3983     }
3984 
3985     return SLCT_NotALiteral;
3986   }
3987   case Stmt::ObjCStringLiteralClass:
3988   case Stmt::StringLiteralClass: {
3989     const StringLiteral *StrE = nullptr;
3990 
3991     if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
3992       StrE = ObjCFExpr->getString();
3993     else
3994       StrE = cast<StringLiteral>(E);
3995 
3996     if (StrE) {
3997       CheckFormatString(S, StrE, E, Args, HasVAListArg, format_idx,
3998                         firstDataArg, Type, InFunctionCall, CallType,
3999                         CheckedVarArgs, UncoveredArg);
4000       return SLCT_CheckedLiteral;
4001     }
4002 
4003     return SLCT_NotALiteral;
4004   }
4005 
4006   default:
4007     return SLCT_NotALiteral;
4008   }
4009 }
4010 
GetFormatStringType(const FormatAttr * Format)4011 Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
4012   return llvm::StringSwitch<FormatStringType>(Format->getType()->getName())
4013   .Case("scanf", FST_Scanf)
4014   .Cases("printf", "printf0", FST_Printf)
4015   .Cases("NSString", "CFString", FST_NSString)
4016   .Case("strftime", FST_Strftime)
4017   .Case("strfmon", FST_Strfmon)
4018   .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
4019   .Case("freebsd_kprintf", FST_FreeBSDKPrintf)
4020   .Case("os_trace", FST_OSTrace)
4021   .Default(FST_Unknown);
4022 }
4023 
4024 /// CheckFormatArguments - Check calls to printf and scanf (and similar
4025 /// functions) for correct use of format strings.
4026 /// Returns true if a format string has been fully checked.
CheckFormatArguments(const FormatAttr * Format,ArrayRef<const Expr * > Args,bool IsCXXMember,VariadicCallType CallType,SourceLocation Loc,SourceRange Range,llvm::SmallBitVector & CheckedVarArgs)4027 bool Sema::CheckFormatArguments(const FormatAttr *Format,
4028                                 ArrayRef<const Expr *> Args,
4029                                 bool IsCXXMember,
4030                                 VariadicCallType CallType,
4031                                 SourceLocation Loc, SourceRange Range,
4032                                 llvm::SmallBitVector &CheckedVarArgs) {
4033   FormatStringInfo FSI;
4034   if (getFormatStringInfo(Format, IsCXXMember, &FSI))
4035     return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx,
4036                                 FSI.FirstDataArg, GetFormatStringType(Format),
4037                                 CallType, Loc, Range, CheckedVarArgs);
4038   return false;
4039 }
4040 
CheckFormatArguments(ArrayRef<const Expr * > Args,bool HasVAListArg,unsigned format_idx,unsigned firstDataArg,FormatStringType Type,VariadicCallType CallType,SourceLocation Loc,SourceRange Range,llvm::SmallBitVector & CheckedVarArgs)4041 bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args,
4042                                 bool HasVAListArg, unsigned format_idx,
4043                                 unsigned firstDataArg, FormatStringType Type,
4044                                 VariadicCallType CallType,
4045                                 SourceLocation Loc, SourceRange Range,
4046                                 llvm::SmallBitVector &CheckedVarArgs) {
4047   // CHECK: printf/scanf-like function is called with no format string.
4048   if (format_idx >= Args.size()) {
4049     Diag(Loc, diag::warn_missing_format_string) << Range;
4050     return false;
4051   }
4052 
4053   const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
4054 
4055   // CHECK: format string is not a string literal.
4056   //
4057   // Dynamically generated format strings are difficult to
4058   // automatically vet at compile time.  Requiring that format strings
4059   // are string literals: (1) permits the checking of format strings by
4060   // the compiler and thereby (2) can practically remove the source of
4061   // many format string exploits.
4062 
4063   // Format string can be either ObjC string (e.g. @"%d") or
4064   // C string (e.g. "%d")
4065   // ObjC string uses the same format specifiers as C string, so we can use
4066   // the same format string checking logic for both ObjC and C strings.
4067   UncoveredArgHandler UncoveredArg;
4068   StringLiteralCheckType CT =
4069       checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg,
4070                             format_idx, firstDataArg, Type, CallType,
4071                             /*IsFunctionCall*/true, CheckedVarArgs,
4072                             UncoveredArg);
4073 
4074   // Generate a diagnostic where an uncovered argument is detected.
4075   if (UncoveredArg.hasUncoveredArg()) {
4076     unsigned ArgIdx = UncoveredArg.getUncoveredArg() + firstDataArg;
4077     assert(ArgIdx < Args.size() && "ArgIdx outside bounds");
4078     UncoveredArg.Diagnose(*this, /*IsFunctionCall*/true, Args[ArgIdx]);
4079   }
4080 
4081   if (CT != SLCT_NotALiteral)
4082     // Literal format string found, check done!
4083     return CT == SLCT_CheckedLiteral;
4084 
4085   // Strftime is particular as it always uses a single 'time' argument,
4086   // so it is safe to pass a non-literal string.
4087   if (Type == FST_Strftime)
4088     return false;
4089 
4090   // Do not emit diag when the string param is a macro expansion and the
4091   // format is either NSString or CFString. This is a hack to prevent
4092   // diag when using the NSLocalizedString and CFCopyLocalizedString macros
4093   // which are usually used in place of NS and CF string literals.
4094   SourceLocation FormatLoc = Args[format_idx]->getLocStart();
4095   if (Type == FST_NSString && SourceMgr.isInSystemMacro(FormatLoc))
4096     return false;
4097 
4098   // If there are no arguments specified, warn with -Wformat-security, otherwise
4099   // warn only with -Wformat-nonliteral.
4100   if (Args.size() == firstDataArg) {
4101     Diag(FormatLoc, diag::warn_format_nonliteral_noargs)
4102       << OrigFormatExpr->getSourceRange();
4103     switch (Type) {
4104     default:
4105       break;
4106     case FST_Kprintf:
4107     case FST_FreeBSDKPrintf:
4108     case FST_Printf:
4109       Diag(FormatLoc, diag::note_format_security_fixit)
4110         << FixItHint::CreateInsertion(FormatLoc, "\"%s\", ");
4111       break;
4112     case FST_NSString:
4113       Diag(FormatLoc, diag::note_format_security_fixit)
4114         << FixItHint::CreateInsertion(FormatLoc, "@\"%@\", ");
4115       break;
4116     }
4117   } else {
4118     Diag(FormatLoc, diag::warn_format_nonliteral)
4119       << OrigFormatExpr->getSourceRange();
4120   }
4121   return false;
4122 }
4123 
4124 namespace {
4125 class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
4126 protected:
4127   Sema &S;
4128   const StringLiteral *FExpr;
4129   const Expr *OrigFormatExpr;
4130   const unsigned FirstDataArg;
4131   const unsigned NumDataArgs;
4132   const char *Beg; // Start of format string.
4133   const bool HasVAListArg;
4134   ArrayRef<const Expr *> Args;
4135   unsigned FormatIdx;
4136   llvm::SmallBitVector CoveredArgs;
4137   bool usesPositionalArgs;
4138   bool atFirstArg;
4139   bool inFunctionCall;
4140   Sema::VariadicCallType CallType;
4141   llvm::SmallBitVector &CheckedVarArgs;
4142   UncoveredArgHandler &UncoveredArg;
4143 
4144 public:
CheckFormatHandler(Sema & s,const StringLiteral * fexpr,const Expr * origFormatExpr,unsigned firstDataArg,unsigned numDataArgs,const char * beg,bool hasVAListArg,ArrayRef<const Expr * > Args,unsigned formatIdx,bool inFunctionCall,Sema::VariadicCallType callType,llvm::SmallBitVector & CheckedVarArgs,UncoveredArgHandler & UncoveredArg)4145   CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
4146                      const Expr *origFormatExpr, unsigned firstDataArg,
4147                      unsigned numDataArgs, const char *beg, bool hasVAListArg,
4148                      ArrayRef<const Expr *> Args,
4149                      unsigned formatIdx, bool inFunctionCall,
4150                      Sema::VariadicCallType callType,
4151                      llvm::SmallBitVector &CheckedVarArgs,
4152                      UncoveredArgHandler &UncoveredArg)
4153     : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
4154       FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
4155       Beg(beg), HasVAListArg(hasVAListArg),
4156       Args(Args), FormatIdx(formatIdx),
4157       usesPositionalArgs(false), atFirstArg(true),
4158       inFunctionCall(inFunctionCall), CallType(callType),
4159       CheckedVarArgs(CheckedVarArgs), UncoveredArg(UncoveredArg) {
4160     CoveredArgs.resize(numDataArgs);
4161     CoveredArgs.reset();
4162   }
4163 
4164   void DoneProcessing();
4165 
4166   void HandleIncompleteSpecifier(const char *startSpecifier,
4167                                  unsigned specifierLen) override;
4168 
4169   void HandleInvalidLengthModifier(
4170                            const analyze_format_string::FormatSpecifier &FS,
4171                            const analyze_format_string::ConversionSpecifier &CS,
4172                            const char *startSpecifier, unsigned specifierLen,
4173                            unsigned DiagID);
4174 
4175   void HandleNonStandardLengthModifier(
4176                     const analyze_format_string::FormatSpecifier &FS,
4177                     const char *startSpecifier, unsigned specifierLen);
4178 
4179   void HandleNonStandardConversionSpecifier(
4180                     const analyze_format_string::ConversionSpecifier &CS,
4181                     const char *startSpecifier, unsigned specifierLen);
4182 
4183   void HandlePosition(const char *startPos, unsigned posLen) override;
4184 
4185   void HandleInvalidPosition(const char *startSpecifier,
4186                              unsigned specifierLen,
4187                              analyze_format_string::PositionContext p) override;
4188 
4189   void HandleZeroPosition(const char *startPos, unsigned posLen) override;
4190 
4191   void HandleNullChar(const char *nullCharacter) override;
4192 
4193   template <typename Range>
4194   static void
4195   EmitFormatDiagnostic(Sema &S, bool inFunctionCall, const Expr *ArgumentExpr,
4196                        const PartialDiagnostic &PDiag, SourceLocation StringLoc,
4197                        bool IsStringLocation, Range StringRange,
4198                        ArrayRef<FixItHint> Fixit = None);
4199 
4200 protected:
4201   bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
4202                                         const char *startSpec,
4203                                         unsigned specifierLen,
4204                                         const char *csStart, unsigned csLen);
4205 
4206   void HandlePositionalNonpositionalArgs(SourceLocation Loc,
4207                                          const char *startSpec,
4208                                          unsigned specifierLen);
4209 
4210   SourceRange getFormatStringRange();
4211   CharSourceRange getSpecifierRange(const char *startSpecifier,
4212                                     unsigned specifierLen);
4213   SourceLocation getLocationOfByte(const char *x);
4214 
4215   const Expr *getDataArg(unsigned i) const;
4216 
4217   bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
4218                     const analyze_format_string::ConversionSpecifier &CS,
4219                     const char *startSpecifier, unsigned specifierLen,
4220                     unsigned argIndex);
4221 
4222   template <typename Range>
4223   void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
4224                             bool IsStringLocation, Range StringRange,
4225                             ArrayRef<FixItHint> Fixit = None);
4226 };
4227 } // end anonymous namespace
4228 
getFormatStringRange()4229 SourceRange CheckFormatHandler::getFormatStringRange() {
4230   return OrigFormatExpr->getSourceRange();
4231 }
4232 
4233 CharSourceRange CheckFormatHandler::
getSpecifierRange(const char * startSpecifier,unsigned specifierLen)4234 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
4235   SourceLocation Start = getLocationOfByte(startSpecifier);
4236   SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
4237 
4238   // Advance the end SourceLocation by one due to half-open ranges.
4239   End = End.getLocWithOffset(1);
4240 
4241   return CharSourceRange::getCharRange(Start, End);
4242 }
4243 
getLocationOfByte(const char * x)4244 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
4245   return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
4246 }
4247 
HandleIncompleteSpecifier(const char * startSpecifier,unsigned specifierLen)4248 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
4249                                                    unsigned specifierLen){
4250   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
4251                        getLocationOfByte(startSpecifier),
4252                        /*IsStringLocation*/true,
4253                        getSpecifierRange(startSpecifier, specifierLen));
4254 }
4255 
HandleInvalidLengthModifier(const analyze_format_string::FormatSpecifier & FS,const analyze_format_string::ConversionSpecifier & CS,const char * startSpecifier,unsigned specifierLen,unsigned DiagID)4256 void CheckFormatHandler::HandleInvalidLengthModifier(
4257     const analyze_format_string::FormatSpecifier &FS,
4258     const analyze_format_string::ConversionSpecifier &CS,
4259     const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
4260   using namespace analyze_format_string;
4261 
4262   const LengthModifier &LM = FS.getLengthModifier();
4263   CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
4264 
4265   // See if we know how to fix this length modifier.
4266   Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
4267   if (FixedLM) {
4268     EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
4269                          getLocationOfByte(LM.getStart()),
4270                          /*IsStringLocation*/true,
4271                          getSpecifierRange(startSpecifier, specifierLen));
4272 
4273     S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
4274       << FixedLM->toString()
4275       << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
4276 
4277   } else {
4278     FixItHint Hint;
4279     if (DiagID == diag::warn_format_nonsensical_length)
4280       Hint = FixItHint::CreateRemoval(LMRange);
4281 
4282     EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
4283                          getLocationOfByte(LM.getStart()),
4284                          /*IsStringLocation*/true,
4285                          getSpecifierRange(startSpecifier, specifierLen),
4286                          Hint);
4287   }
4288 }
4289 
HandleNonStandardLengthModifier(const analyze_format_string::FormatSpecifier & FS,const char * startSpecifier,unsigned specifierLen)4290 void CheckFormatHandler::HandleNonStandardLengthModifier(
4291     const analyze_format_string::FormatSpecifier &FS,
4292     const char *startSpecifier, unsigned specifierLen) {
4293   using namespace analyze_format_string;
4294 
4295   const LengthModifier &LM = FS.getLengthModifier();
4296   CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
4297 
4298   // See if we know how to fix this length modifier.
4299   Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
4300   if (FixedLM) {
4301     EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
4302                            << LM.toString() << 0,
4303                          getLocationOfByte(LM.getStart()),
4304                          /*IsStringLocation*/true,
4305                          getSpecifierRange(startSpecifier, specifierLen));
4306 
4307     S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
4308       << FixedLM->toString()
4309       << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
4310 
4311   } else {
4312     EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
4313                            << LM.toString() << 0,
4314                          getLocationOfByte(LM.getStart()),
4315                          /*IsStringLocation*/true,
4316                          getSpecifierRange(startSpecifier, specifierLen));
4317   }
4318 }
4319 
HandleNonStandardConversionSpecifier(const analyze_format_string::ConversionSpecifier & CS,const char * startSpecifier,unsigned specifierLen)4320 void CheckFormatHandler::HandleNonStandardConversionSpecifier(
4321     const analyze_format_string::ConversionSpecifier &CS,
4322     const char *startSpecifier, unsigned specifierLen) {
4323   using namespace analyze_format_string;
4324 
4325   // See if we know how to fix this conversion specifier.
4326   Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
4327   if (FixedCS) {
4328     EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
4329                           << CS.toString() << /*conversion specifier*/1,
4330                          getLocationOfByte(CS.getStart()),
4331                          /*IsStringLocation*/true,
4332                          getSpecifierRange(startSpecifier, specifierLen));
4333 
4334     CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
4335     S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
4336       << FixedCS->toString()
4337       << FixItHint::CreateReplacement(CSRange, FixedCS->toString());
4338   } else {
4339     EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
4340                           << CS.toString() << /*conversion specifier*/1,
4341                          getLocationOfByte(CS.getStart()),
4342                          /*IsStringLocation*/true,
4343                          getSpecifierRange(startSpecifier, specifierLen));
4344   }
4345 }
4346 
HandlePosition(const char * startPos,unsigned posLen)4347 void CheckFormatHandler::HandlePosition(const char *startPos,
4348                                         unsigned posLen) {
4349   EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
4350                                getLocationOfByte(startPos),
4351                                /*IsStringLocation*/true,
4352                                getSpecifierRange(startPos, posLen));
4353 }
4354 
4355 void
HandleInvalidPosition(const char * startPos,unsigned posLen,analyze_format_string::PositionContext p)4356 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
4357                                      analyze_format_string::PositionContext p) {
4358   EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
4359                          << (unsigned) p,
4360                        getLocationOfByte(startPos), /*IsStringLocation*/true,
4361                        getSpecifierRange(startPos, posLen));
4362 }
4363 
HandleZeroPosition(const char * startPos,unsigned posLen)4364 void CheckFormatHandler::HandleZeroPosition(const char *startPos,
4365                                             unsigned posLen) {
4366   EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
4367                                getLocationOfByte(startPos),
4368                                /*IsStringLocation*/true,
4369                                getSpecifierRange(startPos, posLen));
4370 }
4371 
HandleNullChar(const char * nullCharacter)4372 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
4373   if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
4374     // The presence of a null character is likely an error.
4375     EmitFormatDiagnostic(
4376       S.PDiag(diag::warn_printf_format_string_contains_null_char),
4377       getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
4378       getFormatStringRange());
4379   }
4380 }
4381 
4382 // Note that this may return NULL if there was an error parsing or building
4383 // one of the argument expressions.
getDataArg(unsigned i) const4384 const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
4385   return Args[FirstDataArg + i];
4386 }
4387 
DoneProcessing()4388 void CheckFormatHandler::DoneProcessing() {
4389   // Does the number of data arguments exceed the number of
4390   // format conversions in the format string?
4391   if (!HasVAListArg) {
4392       // Find any arguments that weren't covered.
4393     CoveredArgs.flip();
4394     signed notCoveredArg = CoveredArgs.find_first();
4395     if (notCoveredArg >= 0) {
4396       assert((unsigned)notCoveredArg < NumDataArgs);
4397       UncoveredArg.Update(notCoveredArg, OrigFormatExpr);
4398     } else {
4399       UncoveredArg.setAllCovered();
4400     }
4401   }
4402 }
4403 
Diagnose(Sema & S,bool IsFunctionCall,const Expr * ArgExpr)4404 void UncoveredArgHandler::Diagnose(Sema &S, bool IsFunctionCall,
4405                                    const Expr *ArgExpr) {
4406   assert(hasUncoveredArg() && DiagnosticExprs.size() > 0 &&
4407          "Invalid state");
4408 
4409   if (!ArgExpr)
4410     return;
4411 
4412   SourceLocation Loc = ArgExpr->getLocStart();
4413 
4414   if (S.getSourceManager().isInSystemMacro(Loc))
4415     return;
4416 
4417   PartialDiagnostic PDiag = S.PDiag(diag::warn_printf_data_arg_not_used);
4418   for (auto E : DiagnosticExprs)
4419     PDiag << E->getSourceRange();
4420 
4421   CheckFormatHandler::EmitFormatDiagnostic(
4422                                   S, IsFunctionCall, DiagnosticExprs[0],
4423                                   PDiag, Loc, /*IsStringLocation*/false,
4424                                   DiagnosticExprs[0]->getSourceRange());
4425 }
4426 
4427 bool
HandleInvalidConversionSpecifier(unsigned argIndex,SourceLocation Loc,const char * startSpec,unsigned specifierLen,const char * csStart,unsigned csLen)4428 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
4429                                                      SourceLocation Loc,
4430                                                      const char *startSpec,
4431                                                      unsigned specifierLen,
4432                                                      const char *csStart,
4433                                                      unsigned csLen) {
4434   bool keepGoing = true;
4435   if (argIndex < NumDataArgs) {
4436     // Consider the argument coverered, even though the specifier doesn't
4437     // make sense.
4438     CoveredArgs.set(argIndex);
4439   }
4440   else {
4441     // If argIndex exceeds the number of data arguments we
4442     // don't issue a warning because that is just a cascade of warnings (and
4443     // they may have intended '%%' anyway). We don't want to continue processing
4444     // the format string after this point, however, as we will like just get
4445     // gibberish when trying to match arguments.
4446     keepGoing = false;
4447   }
4448 
4449   StringRef Specifier(csStart, csLen);
4450 
4451   // If the specifier in non-printable, it could be the first byte of a UTF-8
4452   // sequence. In that case, print the UTF-8 code point. If not, print the byte
4453   // hex value.
4454   std::string CodePointStr;
4455   if (!llvm::sys::locale::isPrint(*csStart)) {
4456     UTF32 CodePoint;
4457     const UTF8 **B = reinterpret_cast<const UTF8 **>(&csStart);
4458     const UTF8 *E =
4459         reinterpret_cast<const UTF8 *>(csStart + csLen);
4460     ConversionResult Result =
4461         llvm::convertUTF8Sequence(B, E, &CodePoint, strictConversion);
4462 
4463     if (Result != conversionOK) {
4464       unsigned char FirstChar = *csStart;
4465       CodePoint = (UTF32)FirstChar;
4466     }
4467 
4468     llvm::raw_string_ostream OS(CodePointStr);
4469     if (CodePoint < 256)
4470       OS << "\\x" << llvm::format("%02x", CodePoint);
4471     else if (CodePoint <= 0xFFFF)
4472       OS << "\\u" << llvm::format("%04x", CodePoint);
4473     else
4474       OS << "\\U" << llvm::format("%08x", CodePoint);
4475     OS.flush();
4476     Specifier = CodePointStr;
4477   }
4478 
4479   EmitFormatDiagnostic(
4480       S.PDiag(diag::warn_format_invalid_conversion) << Specifier, Loc,
4481       /*IsStringLocation*/ true, getSpecifierRange(startSpec, specifierLen));
4482 
4483   return keepGoing;
4484 }
4485 
4486 void
HandlePositionalNonpositionalArgs(SourceLocation Loc,const char * startSpec,unsigned specifierLen)4487 CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
4488                                                       const char *startSpec,
4489                                                       unsigned specifierLen) {
4490   EmitFormatDiagnostic(
4491     S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
4492     Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
4493 }
4494 
4495 bool
CheckNumArgs(const analyze_format_string::FormatSpecifier & FS,const analyze_format_string::ConversionSpecifier & CS,const char * startSpecifier,unsigned specifierLen,unsigned argIndex)4496 CheckFormatHandler::CheckNumArgs(
4497   const analyze_format_string::FormatSpecifier &FS,
4498   const analyze_format_string::ConversionSpecifier &CS,
4499   const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
4500 
4501   if (argIndex >= NumDataArgs) {
4502     PartialDiagnostic PDiag = FS.usesPositionalArg()
4503       ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
4504            << (argIndex+1) << NumDataArgs)
4505       : S.PDiag(diag::warn_printf_insufficient_data_args);
4506     EmitFormatDiagnostic(
4507       PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
4508       getSpecifierRange(startSpecifier, specifierLen));
4509 
4510     // Since more arguments than conversion tokens are given, by extension
4511     // all arguments are covered, so mark this as so.
4512     UncoveredArg.setAllCovered();
4513     return false;
4514   }
4515   return true;
4516 }
4517 
4518 template<typename Range>
EmitFormatDiagnostic(PartialDiagnostic PDiag,SourceLocation Loc,bool IsStringLocation,Range StringRange,ArrayRef<FixItHint> FixIt)4519 void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
4520                                               SourceLocation Loc,
4521                                               bool IsStringLocation,
4522                                               Range StringRange,
4523                                               ArrayRef<FixItHint> FixIt) {
4524   EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
4525                        Loc, IsStringLocation, StringRange, FixIt);
4526 }
4527 
4528 /// \brief If the format string is not within the funcion call, emit a note
4529 /// so that the function call and string are in diagnostic messages.
4530 ///
4531 /// \param InFunctionCall if true, the format string is within the function
4532 /// call and only one diagnostic message will be produced.  Otherwise, an
4533 /// extra note will be emitted pointing to location of the format string.
4534 ///
4535 /// \param ArgumentExpr the expression that is passed as the format string
4536 /// argument in the function call.  Used for getting locations when two
4537 /// diagnostics are emitted.
4538 ///
4539 /// \param PDiag the callee should already have provided any strings for the
4540 /// diagnostic message.  This function only adds locations and fixits
4541 /// to diagnostics.
4542 ///
4543 /// \param Loc primary location for diagnostic.  If two diagnostics are
4544 /// required, one will be at Loc and a new SourceLocation will be created for
4545 /// the other one.
4546 ///
4547 /// \param IsStringLocation if true, Loc points to the format string should be
4548 /// used for the note.  Otherwise, Loc points to the argument list and will
4549 /// be used with PDiag.
4550 ///
4551 /// \param StringRange some or all of the string to highlight.  This is
4552 /// templated so it can accept either a CharSourceRange or a SourceRange.
4553 ///
4554 /// \param FixIt optional fix it hint for the format string.
4555 template <typename Range>
EmitFormatDiagnostic(Sema & S,bool InFunctionCall,const Expr * ArgumentExpr,const PartialDiagnostic & PDiag,SourceLocation Loc,bool IsStringLocation,Range StringRange,ArrayRef<FixItHint> FixIt)4556 void CheckFormatHandler::EmitFormatDiagnostic(
4557     Sema &S, bool InFunctionCall, const Expr *ArgumentExpr,
4558     const PartialDiagnostic &PDiag, SourceLocation Loc, bool IsStringLocation,
4559     Range StringRange, ArrayRef<FixItHint> FixIt) {
4560   if (InFunctionCall) {
4561     const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
4562     D << StringRange;
4563     D << FixIt;
4564   } else {
4565     S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
4566       << ArgumentExpr->getSourceRange();
4567 
4568     const Sema::SemaDiagnosticBuilder &Note =
4569       S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
4570              diag::note_format_string_defined);
4571 
4572     Note << StringRange;
4573     Note << FixIt;
4574   }
4575 }
4576 
4577 //===--- CHECK: Printf format string checking ------------------------------===//
4578 
4579 namespace {
4580 class CheckPrintfHandler : public CheckFormatHandler {
4581   bool ObjCContext;
4582 
4583 public:
CheckPrintfHandler(Sema & s,const StringLiteral * fexpr,const Expr * origFormatExpr,unsigned firstDataArg,unsigned numDataArgs,bool isObjC,const char * beg,bool hasVAListArg,ArrayRef<const Expr * > Args,unsigned formatIdx,bool inFunctionCall,Sema::VariadicCallType CallType,llvm::SmallBitVector & CheckedVarArgs,UncoveredArgHandler & UncoveredArg)4584   CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
4585                      const Expr *origFormatExpr, unsigned firstDataArg,
4586                      unsigned numDataArgs, bool isObjC,
4587                      const char *beg, bool hasVAListArg,
4588                      ArrayRef<const Expr *> Args,
4589                      unsigned formatIdx, bool inFunctionCall,
4590                      Sema::VariadicCallType CallType,
4591                      llvm::SmallBitVector &CheckedVarArgs,
4592                      UncoveredArgHandler &UncoveredArg)
4593     : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
4594                          numDataArgs, beg, hasVAListArg, Args,
4595                          formatIdx, inFunctionCall, CallType, CheckedVarArgs,
4596                          UncoveredArg),
4597       ObjCContext(isObjC)
4598   {}
4599 
4600   bool HandleInvalidPrintfConversionSpecifier(
4601                                       const analyze_printf::PrintfSpecifier &FS,
4602                                       const char *startSpecifier,
4603                                       unsigned specifierLen) override;
4604 
4605   bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
4606                              const char *startSpecifier,
4607                              unsigned specifierLen) override;
4608   bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
4609                        const char *StartSpecifier,
4610                        unsigned SpecifierLen,
4611                        const Expr *E);
4612 
4613   bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
4614                     const char *startSpecifier, unsigned specifierLen);
4615   void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
4616                            const analyze_printf::OptionalAmount &Amt,
4617                            unsigned type,
4618                            const char *startSpecifier, unsigned specifierLen);
4619   void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
4620                   const analyze_printf::OptionalFlag &flag,
4621                   const char *startSpecifier, unsigned specifierLen);
4622   void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
4623                          const analyze_printf::OptionalFlag &ignoredFlag,
4624                          const analyze_printf::OptionalFlag &flag,
4625                          const char *startSpecifier, unsigned specifierLen);
4626   bool checkForCStrMembers(const analyze_printf::ArgType &AT,
4627                            const Expr *E);
4628 
4629   void HandleEmptyObjCModifierFlag(const char *startFlag,
4630                                    unsigned flagLen) override;
4631 
4632   void HandleInvalidObjCModifierFlag(const char *startFlag,
4633                                             unsigned flagLen) override;
4634 
4635   void HandleObjCFlagsWithNonObjCConversion(const char *flagsStart,
4636                                            const char *flagsEnd,
4637                                            const char *conversionPosition)
4638                                              override;
4639 };
4640 } // end anonymous namespace
4641 
HandleInvalidPrintfConversionSpecifier(const analyze_printf::PrintfSpecifier & FS,const char * startSpecifier,unsigned specifierLen)4642 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
4643                                       const analyze_printf::PrintfSpecifier &FS,
4644                                       const char *startSpecifier,
4645                                       unsigned specifierLen) {
4646   const analyze_printf::PrintfConversionSpecifier &CS =
4647     FS.getConversionSpecifier();
4648 
4649   return HandleInvalidConversionSpecifier(FS.getArgIndex(),
4650                                           getLocationOfByte(CS.getStart()),
4651                                           startSpecifier, specifierLen,
4652                                           CS.getStart(), CS.getLength());
4653 }
4654 
HandleAmount(const analyze_format_string::OptionalAmount & Amt,unsigned k,const char * startSpecifier,unsigned specifierLen)4655 bool CheckPrintfHandler::HandleAmount(
4656                                const analyze_format_string::OptionalAmount &Amt,
4657                                unsigned k, const char *startSpecifier,
4658                                unsigned specifierLen) {
4659   if (Amt.hasDataArgument()) {
4660     if (!HasVAListArg) {
4661       unsigned argIndex = Amt.getArgIndex();
4662       if (argIndex >= NumDataArgs) {
4663         EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
4664                                << k,
4665                              getLocationOfByte(Amt.getStart()),
4666                              /*IsStringLocation*/true,
4667                              getSpecifierRange(startSpecifier, specifierLen));
4668         // Don't do any more checking.  We will just emit
4669         // spurious errors.
4670         return false;
4671       }
4672 
4673       // Type check the data argument.  It should be an 'int'.
4674       // Although not in conformance with C99, we also allow the argument to be
4675       // an 'unsigned int' as that is a reasonably safe case.  GCC also
4676       // doesn't emit a warning for that case.
4677       CoveredArgs.set(argIndex);
4678       const Expr *Arg = getDataArg(argIndex);
4679       if (!Arg)
4680         return false;
4681 
4682       QualType T = Arg->getType();
4683 
4684       const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
4685       assert(AT.isValid());
4686 
4687       if (!AT.matchesType(S.Context, T)) {
4688         EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
4689                                << k << AT.getRepresentativeTypeName(S.Context)
4690                                << T << Arg->getSourceRange(),
4691                              getLocationOfByte(Amt.getStart()),
4692                              /*IsStringLocation*/true,
4693                              getSpecifierRange(startSpecifier, specifierLen));
4694         // Don't do any more checking.  We will just emit
4695         // spurious errors.
4696         return false;
4697       }
4698     }
4699   }
4700   return true;
4701 }
4702 
HandleInvalidAmount(const analyze_printf::PrintfSpecifier & FS,const analyze_printf::OptionalAmount & Amt,unsigned type,const char * startSpecifier,unsigned specifierLen)4703 void CheckPrintfHandler::HandleInvalidAmount(
4704                                       const analyze_printf::PrintfSpecifier &FS,
4705                                       const analyze_printf::OptionalAmount &Amt,
4706                                       unsigned type,
4707                                       const char *startSpecifier,
4708                                       unsigned specifierLen) {
4709   const analyze_printf::PrintfConversionSpecifier &CS =
4710     FS.getConversionSpecifier();
4711 
4712   FixItHint fixit =
4713     Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
4714       ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
4715                                  Amt.getConstantLength()))
4716       : FixItHint();
4717 
4718   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
4719                          << type << CS.toString(),
4720                        getLocationOfByte(Amt.getStart()),
4721                        /*IsStringLocation*/true,
4722                        getSpecifierRange(startSpecifier, specifierLen),
4723                        fixit);
4724 }
4725 
HandleFlag(const analyze_printf::PrintfSpecifier & FS,const analyze_printf::OptionalFlag & flag,const char * startSpecifier,unsigned specifierLen)4726 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
4727                                     const analyze_printf::OptionalFlag &flag,
4728                                     const char *startSpecifier,
4729                                     unsigned specifierLen) {
4730   // Warn about pointless flag with a fixit removal.
4731   const analyze_printf::PrintfConversionSpecifier &CS =
4732     FS.getConversionSpecifier();
4733   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
4734                          << flag.toString() << CS.toString(),
4735                        getLocationOfByte(flag.getPosition()),
4736                        /*IsStringLocation*/true,
4737                        getSpecifierRange(startSpecifier, specifierLen),
4738                        FixItHint::CreateRemoval(
4739                          getSpecifierRange(flag.getPosition(), 1)));
4740 }
4741 
HandleIgnoredFlag(const analyze_printf::PrintfSpecifier & FS,const analyze_printf::OptionalFlag & ignoredFlag,const analyze_printf::OptionalFlag & flag,const char * startSpecifier,unsigned specifierLen)4742 void CheckPrintfHandler::HandleIgnoredFlag(
4743                                 const analyze_printf::PrintfSpecifier &FS,
4744                                 const analyze_printf::OptionalFlag &ignoredFlag,
4745                                 const analyze_printf::OptionalFlag &flag,
4746                                 const char *startSpecifier,
4747                                 unsigned specifierLen) {
4748   // Warn about ignored flag with a fixit removal.
4749   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
4750                          << ignoredFlag.toString() << flag.toString(),
4751                        getLocationOfByte(ignoredFlag.getPosition()),
4752                        /*IsStringLocation*/true,
4753                        getSpecifierRange(startSpecifier, specifierLen),
4754                        FixItHint::CreateRemoval(
4755                          getSpecifierRange(ignoredFlag.getPosition(), 1)));
4756 }
4757 
4758 //  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
4759 //                            bool IsStringLocation, Range StringRange,
4760 //                            ArrayRef<FixItHint> Fixit = None);
4761 
HandleEmptyObjCModifierFlag(const char * startFlag,unsigned flagLen)4762 void CheckPrintfHandler::HandleEmptyObjCModifierFlag(const char *startFlag,
4763                                                      unsigned flagLen) {
4764   // Warn about an empty flag.
4765   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_empty_objc_flag),
4766                        getLocationOfByte(startFlag),
4767                        /*IsStringLocation*/true,
4768                        getSpecifierRange(startFlag, flagLen));
4769 }
4770 
HandleInvalidObjCModifierFlag(const char * startFlag,unsigned flagLen)4771 void CheckPrintfHandler::HandleInvalidObjCModifierFlag(const char *startFlag,
4772                                                        unsigned flagLen) {
4773   // Warn about an invalid flag.
4774   auto Range = getSpecifierRange(startFlag, flagLen);
4775   StringRef flag(startFlag, flagLen);
4776   EmitFormatDiagnostic(S.PDiag(diag::warn_printf_invalid_objc_flag) << flag,
4777                       getLocationOfByte(startFlag),
4778                       /*IsStringLocation*/true,
4779                       Range, FixItHint::CreateRemoval(Range));
4780 }
4781 
HandleObjCFlagsWithNonObjCConversion(const char * flagsStart,const char * flagsEnd,const char * conversionPosition)4782 void CheckPrintfHandler::HandleObjCFlagsWithNonObjCConversion(
4783     const char *flagsStart, const char *flagsEnd, const char *conversionPosition) {
4784     // Warn about using '[...]' without a '@' conversion.
4785     auto Range = getSpecifierRange(flagsStart, flagsEnd - flagsStart + 1);
4786     auto diag = diag::warn_printf_ObjCflags_without_ObjCConversion;
4787     EmitFormatDiagnostic(S.PDiag(diag) << StringRef(conversionPosition, 1),
4788                          getLocationOfByte(conversionPosition),
4789                          /*IsStringLocation*/true,
4790                          Range, FixItHint::CreateRemoval(Range));
4791 }
4792 
4793 // Determines if the specified is a C++ class or struct containing
4794 // a member with the specified name and kind (e.g. a CXXMethodDecl named
4795 // "c_str()").
4796 template<typename MemberKind>
4797 static llvm::SmallPtrSet<MemberKind*, 1>
CXXRecordMembersNamed(StringRef Name,Sema & S,QualType Ty)4798 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
4799   const RecordType *RT = Ty->getAs<RecordType>();
4800   llvm::SmallPtrSet<MemberKind*, 1> Results;
4801 
4802   if (!RT)
4803     return Results;
4804   const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
4805   if (!RD || !RD->getDefinition())
4806     return Results;
4807 
4808   LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(),
4809                  Sema::LookupMemberName);
4810   R.suppressDiagnostics();
4811 
4812   // We just need to include all members of the right kind turned up by the
4813   // filter, at this point.
4814   if (S.LookupQualifiedName(R, RT->getDecl()))
4815     for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
4816       NamedDecl *decl = (*I)->getUnderlyingDecl();
4817       if (MemberKind *FK = dyn_cast<MemberKind>(decl))
4818         Results.insert(FK);
4819     }
4820   return Results;
4821 }
4822 
4823 /// Check if we could call '.c_str()' on an object.
4824 ///
4825 /// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't
4826 /// allow the call, or if it would be ambiguous).
hasCStrMethod(const Expr * E)4827 bool Sema::hasCStrMethod(const Expr *E) {
4828   typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
4829   MethodSet Results =
4830       CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType());
4831   for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
4832        MI != ME; ++MI)
4833     if ((*MI)->getMinRequiredArguments() == 0)
4834       return true;
4835   return false;
4836 }
4837 
4838 // Check if a (w)string was passed when a (w)char* was needed, and offer a
4839 // better diagnostic if so. AT is assumed to be valid.
4840 // Returns true when a c_str() conversion method is found.
checkForCStrMembers(const analyze_printf::ArgType & AT,const Expr * E)4841 bool CheckPrintfHandler::checkForCStrMembers(
4842     const analyze_printf::ArgType &AT, const Expr *E) {
4843   typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
4844 
4845   MethodSet Results =
4846       CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
4847 
4848   for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
4849        MI != ME; ++MI) {
4850     const CXXMethodDecl *Method = *MI;
4851     if (Method->getMinRequiredArguments() == 0 &&
4852         AT.matchesType(S.Context, Method->getReturnType())) {
4853       // FIXME: Suggest parens if the expression needs them.
4854       SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd());
4855       S.Diag(E->getLocStart(), diag::note_printf_c_str)
4856           << "c_str()"
4857           << FixItHint::CreateInsertion(EndLoc, ".c_str()");
4858       return true;
4859     }
4860   }
4861 
4862   return false;
4863 }
4864 
4865 bool
HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier & FS,const char * startSpecifier,unsigned specifierLen)4866 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
4867                                             &FS,
4868                                           const char *startSpecifier,
4869                                           unsigned specifierLen) {
4870   using namespace analyze_format_string;
4871   using namespace analyze_printf;
4872   const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
4873 
4874   if (FS.consumesDataArgument()) {
4875     if (atFirstArg) {
4876         atFirstArg = false;
4877         usesPositionalArgs = FS.usesPositionalArg();
4878     }
4879     else if (usesPositionalArgs != FS.usesPositionalArg()) {
4880       HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
4881                                         startSpecifier, specifierLen);
4882       return false;
4883     }
4884   }
4885 
4886   // First check if the field width, precision, and conversion specifier
4887   // have matching data arguments.
4888   if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
4889                     startSpecifier, specifierLen)) {
4890     return false;
4891   }
4892 
4893   if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
4894                     startSpecifier, specifierLen)) {
4895     return false;
4896   }
4897 
4898   if (!CS.consumesDataArgument()) {
4899     // FIXME: Technically specifying a precision or field width here
4900     // makes no sense.  Worth issuing a warning at some point.
4901     return true;
4902   }
4903 
4904   // Consume the argument.
4905   unsigned argIndex = FS.getArgIndex();
4906   if (argIndex < NumDataArgs) {
4907     // The check to see if the argIndex is valid will come later.
4908     // We set the bit here because we may exit early from this
4909     // function if we encounter some other error.
4910     CoveredArgs.set(argIndex);
4911   }
4912 
4913   // FreeBSD kernel extensions.
4914   if (CS.getKind() == ConversionSpecifier::FreeBSDbArg ||
4915       CS.getKind() == ConversionSpecifier::FreeBSDDArg) {
4916     // We need at least two arguments.
4917     if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex + 1))
4918       return false;
4919 
4920     // Claim the second argument.
4921     CoveredArgs.set(argIndex + 1);
4922 
4923     // Type check the first argument (int for %b, pointer for %D)
4924     const Expr *Ex = getDataArg(argIndex);
4925     const analyze_printf::ArgType &AT =
4926       (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ?
4927         ArgType(S.Context.IntTy) : ArgType::CPointerTy;
4928     if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType()))
4929       EmitFormatDiagnostic(
4930         S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
4931         << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
4932         << false << Ex->getSourceRange(),
4933         Ex->getLocStart(), /*IsStringLocation*/false,
4934         getSpecifierRange(startSpecifier, specifierLen));
4935 
4936     // Type check the second argument (char * for both %b and %D)
4937     Ex = getDataArg(argIndex + 1);
4938     const analyze_printf::ArgType &AT2 = ArgType::CStrTy;
4939     if (AT2.isValid() && !AT2.matchesType(S.Context, Ex->getType()))
4940       EmitFormatDiagnostic(
4941         S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
4942         << AT2.getRepresentativeTypeName(S.Context) << Ex->getType()
4943         << false << Ex->getSourceRange(),
4944         Ex->getLocStart(), /*IsStringLocation*/false,
4945         getSpecifierRange(startSpecifier, specifierLen));
4946 
4947      return true;
4948   }
4949 
4950   // Check for using an Objective-C specific conversion specifier
4951   // in a non-ObjC literal.
4952   if (!ObjCContext && CS.isObjCArg()) {
4953     return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
4954                                                   specifierLen);
4955   }
4956 
4957   // Check for invalid use of field width
4958   if (!FS.hasValidFieldWidth()) {
4959     HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
4960         startSpecifier, specifierLen);
4961   }
4962 
4963   // Check for invalid use of precision
4964   if (!FS.hasValidPrecision()) {
4965     HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
4966         startSpecifier, specifierLen);
4967   }
4968 
4969   // Check each flag does not conflict with any other component.
4970   if (!FS.hasValidThousandsGroupingPrefix())
4971     HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
4972   if (!FS.hasValidLeadingZeros())
4973     HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
4974   if (!FS.hasValidPlusPrefix())
4975     HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
4976   if (!FS.hasValidSpacePrefix())
4977     HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
4978   if (!FS.hasValidAlternativeForm())
4979     HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
4980   if (!FS.hasValidLeftJustified())
4981     HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
4982 
4983   // Check that flags are not ignored by another flag
4984   if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
4985     HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
4986         startSpecifier, specifierLen);
4987   if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
4988     HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
4989             startSpecifier, specifierLen);
4990 
4991   // Check the length modifier is valid with the given conversion specifier.
4992   if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
4993     HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4994                                 diag::warn_format_nonsensical_length);
4995   else if (!FS.hasStandardLengthModifier())
4996     HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
4997   else if (!FS.hasStandardLengthConversionCombination())
4998     HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4999                                 diag::warn_format_non_standard_conversion_spec);
5000 
5001   if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
5002     HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
5003 
5004   // The remaining checks depend on the data arguments.
5005   if (HasVAListArg)
5006     return true;
5007 
5008   if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
5009     return false;
5010 
5011   const Expr *Arg = getDataArg(argIndex);
5012   if (!Arg)
5013     return true;
5014 
5015   return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
5016 }
5017 
requiresParensToAddCast(const Expr * E)5018 static bool requiresParensToAddCast(const Expr *E) {
5019   // FIXME: We should have a general way to reason about operator
5020   // precedence and whether parens are actually needed here.
5021   // Take care of a few common cases where they aren't.
5022   const Expr *Inside = E->IgnoreImpCasts();
5023   if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
5024     Inside = POE->getSyntacticForm()->IgnoreImpCasts();
5025 
5026   switch (Inside->getStmtClass()) {
5027   case Stmt::ArraySubscriptExprClass:
5028   case Stmt::CallExprClass:
5029   case Stmt::CharacterLiteralClass:
5030   case Stmt::CXXBoolLiteralExprClass:
5031   case Stmt::DeclRefExprClass:
5032   case Stmt::FloatingLiteralClass:
5033   case Stmt::IntegerLiteralClass:
5034   case Stmt::MemberExprClass:
5035   case Stmt::ObjCArrayLiteralClass:
5036   case Stmt::ObjCBoolLiteralExprClass:
5037   case Stmt::ObjCBoxedExprClass:
5038   case Stmt::ObjCDictionaryLiteralClass:
5039   case Stmt::ObjCEncodeExprClass:
5040   case Stmt::ObjCIvarRefExprClass:
5041   case Stmt::ObjCMessageExprClass:
5042   case Stmt::ObjCPropertyRefExprClass:
5043   case Stmt::ObjCStringLiteralClass:
5044   case Stmt::ObjCSubscriptRefExprClass:
5045   case Stmt::ParenExprClass:
5046   case Stmt::StringLiteralClass:
5047   case Stmt::UnaryOperatorClass:
5048     return false;
5049   default:
5050     return true;
5051   }
5052 }
5053 
5054 static std::pair<QualType, StringRef>
shouldNotPrintDirectly(const ASTContext & Context,QualType IntendedTy,const Expr * E)5055 shouldNotPrintDirectly(const ASTContext &Context,
5056                        QualType IntendedTy,
5057                        const Expr *E) {
5058   // Use a 'while' to peel off layers of typedefs.
5059   QualType TyTy = IntendedTy;
5060   while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) {
5061     StringRef Name = UserTy->getDecl()->getName();
5062     QualType CastTy = llvm::StringSwitch<QualType>(Name)
5063       .Case("NSInteger", Context.LongTy)
5064       .Case("NSUInteger", Context.UnsignedLongTy)
5065       .Case("SInt32", Context.IntTy)
5066       .Case("UInt32", Context.UnsignedIntTy)
5067       .Default(QualType());
5068 
5069     if (!CastTy.isNull())
5070       return std::make_pair(CastTy, Name);
5071 
5072     TyTy = UserTy->desugar();
5073   }
5074 
5075   // Strip parens if necessary.
5076   if (const ParenExpr *PE = dyn_cast<ParenExpr>(E))
5077     return shouldNotPrintDirectly(Context,
5078                                   PE->getSubExpr()->getType(),
5079                                   PE->getSubExpr());
5080 
5081   // If this is a conditional expression, then its result type is constructed
5082   // via usual arithmetic conversions and thus there might be no necessary
5083   // typedef sugar there.  Recurse to operands to check for NSInteger &
5084   // Co. usage condition.
5085   if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
5086     QualType TrueTy, FalseTy;
5087     StringRef TrueName, FalseName;
5088 
5089     std::tie(TrueTy, TrueName) =
5090       shouldNotPrintDirectly(Context,
5091                              CO->getTrueExpr()->getType(),
5092                              CO->getTrueExpr());
5093     std::tie(FalseTy, FalseName) =
5094       shouldNotPrintDirectly(Context,
5095                              CO->getFalseExpr()->getType(),
5096                              CO->getFalseExpr());
5097 
5098     if (TrueTy == FalseTy)
5099       return std::make_pair(TrueTy, TrueName);
5100     else if (TrueTy.isNull())
5101       return std::make_pair(FalseTy, FalseName);
5102     else if (FalseTy.isNull())
5103       return std::make_pair(TrueTy, TrueName);
5104   }
5105 
5106   return std::make_pair(QualType(), StringRef());
5107 }
5108 
5109 bool
checkFormatExpr(const analyze_printf::PrintfSpecifier & FS,const char * StartSpecifier,unsigned SpecifierLen,const Expr * E)5110 CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
5111                                     const char *StartSpecifier,
5112                                     unsigned SpecifierLen,
5113                                     const Expr *E) {
5114   using namespace analyze_format_string;
5115   using namespace analyze_printf;
5116   // Now type check the data expression that matches the
5117   // format specifier.
5118   const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
5119                                                     ObjCContext);
5120   if (!AT.isValid())
5121     return true;
5122 
5123   QualType ExprTy = E->getType();
5124   while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) {
5125     ExprTy = TET->getUnderlyingExpr()->getType();
5126   }
5127 
5128   analyze_printf::ArgType::MatchKind match = AT.matchesType(S.Context, ExprTy);
5129 
5130   if (match == analyze_printf::ArgType::Match) {
5131     return true;
5132   }
5133 
5134   // Look through argument promotions for our error message's reported type.
5135   // This includes the integral and floating promotions, but excludes array
5136   // and function pointer decay; seeing that an argument intended to be a
5137   // string has type 'char [6]' is probably more confusing than 'char *'.
5138   if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
5139     if (ICE->getCastKind() == CK_IntegralCast ||
5140         ICE->getCastKind() == CK_FloatingCast) {
5141       E = ICE->getSubExpr();
5142       ExprTy = E->getType();
5143 
5144       // Check if we didn't match because of an implicit cast from a 'char'
5145       // or 'short' to an 'int'.  This is done because printf is a varargs
5146       // function.
5147       if (ICE->getType() == S.Context.IntTy ||
5148           ICE->getType() == S.Context.UnsignedIntTy) {
5149         // All further checking is done on the subexpression.
5150         if (AT.matchesType(S.Context, ExprTy))
5151           return true;
5152       }
5153     }
5154   } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) {
5155     // Special case for 'a', which has type 'int' in C.
5156     // Note, however, that we do /not/ want to treat multibyte constants like
5157     // 'MooV' as characters! This form is deprecated but still exists.
5158     if (ExprTy == S.Context.IntTy)
5159       if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue()))
5160         ExprTy = S.Context.CharTy;
5161   }
5162 
5163   // Look through enums to their underlying type.
5164   bool IsEnum = false;
5165   if (auto EnumTy = ExprTy->getAs<EnumType>()) {
5166     ExprTy = EnumTy->getDecl()->getIntegerType();
5167     IsEnum = true;
5168   }
5169 
5170   // %C in an Objective-C context prints a unichar, not a wchar_t.
5171   // If the argument is an integer of some kind, believe the %C and suggest
5172   // a cast instead of changing the conversion specifier.
5173   QualType IntendedTy = ExprTy;
5174   if (ObjCContext &&
5175       FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) {
5176     if (ExprTy->isIntegralOrUnscopedEnumerationType() &&
5177         !ExprTy->isCharType()) {
5178       // 'unichar' is defined as a typedef of unsigned short, but we should
5179       // prefer using the typedef if it is visible.
5180       IntendedTy = S.Context.UnsignedShortTy;
5181 
5182       // While we are here, check if the value is an IntegerLiteral that happens
5183       // to be within the valid range.
5184       if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) {
5185         const llvm::APInt &V = IL->getValue();
5186         if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy))
5187           return true;
5188       }
5189 
5190       LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(),
5191                           Sema::LookupOrdinaryName);
5192       if (S.LookupName(Result, S.getCurScope())) {
5193         NamedDecl *ND = Result.getFoundDecl();
5194         if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND))
5195           if (TD->getUnderlyingType() == IntendedTy)
5196             IntendedTy = S.Context.getTypedefType(TD);
5197       }
5198     }
5199   }
5200 
5201   // Special-case some of Darwin's platform-independence types by suggesting
5202   // casts to primitive types that are known to be large enough.
5203   bool ShouldNotPrintDirectly = false; StringRef CastTyName;
5204   if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
5205     QualType CastTy;
5206     std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E);
5207     if (!CastTy.isNull()) {
5208       IntendedTy = CastTy;
5209       ShouldNotPrintDirectly = true;
5210     }
5211   }
5212 
5213   // We may be able to offer a FixItHint if it is a supported type.
5214   PrintfSpecifier fixedFS = FS;
5215   bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
5216                                  S.Context, ObjCContext);
5217 
5218   if (success) {
5219     // Get the fix string from the fixed format specifier
5220     SmallString<16> buf;
5221     llvm::raw_svector_ostream os(buf);
5222     fixedFS.toString(os);
5223 
5224     CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
5225 
5226     if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) {
5227       unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
5228       if (match == analyze_format_string::ArgType::NoMatchPedantic) {
5229         diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
5230       }
5231       // In this case, the specifier is wrong and should be changed to match
5232       // the argument.
5233       EmitFormatDiagnostic(S.PDiag(diag)
5234                                << AT.getRepresentativeTypeName(S.Context)
5235                                << IntendedTy << IsEnum << E->getSourceRange(),
5236                            E->getLocStart(),
5237                            /*IsStringLocation*/ false, SpecRange,
5238                            FixItHint::CreateReplacement(SpecRange, os.str()));
5239     } else {
5240       // The canonical type for formatting this value is different from the
5241       // actual type of the expression. (This occurs, for example, with Darwin's
5242       // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
5243       // should be printed as 'long' for 64-bit compatibility.)
5244       // Rather than emitting a normal format/argument mismatch, we want to
5245       // add a cast to the recommended type (and correct the format string
5246       // if necessary).
5247       SmallString<16> CastBuf;
5248       llvm::raw_svector_ostream CastFix(CastBuf);
5249       CastFix << "(";
5250       IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
5251       CastFix << ")";
5252 
5253       SmallVector<FixItHint,4> Hints;
5254       if (!AT.matchesType(S.Context, IntendedTy))
5255         Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
5256 
5257       if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
5258         // If there's already a cast present, just replace it.
5259         SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
5260         Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
5261 
5262       } else if (!requiresParensToAddCast(E)) {
5263         // If the expression has high enough precedence,
5264         // just write the C-style cast.
5265         Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
5266                                                    CastFix.str()));
5267       } else {
5268         // Otherwise, add parens around the expression as well as the cast.
5269         CastFix << "(";
5270         Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
5271                                                    CastFix.str()));
5272 
5273         SourceLocation After = S.getLocForEndOfToken(E->getLocEnd());
5274         Hints.push_back(FixItHint::CreateInsertion(After, ")"));
5275       }
5276 
5277       if (ShouldNotPrintDirectly) {
5278         // The expression has a type that should not be printed directly.
5279         // We extract the name from the typedef because we don't want to show
5280         // the underlying type in the diagnostic.
5281         StringRef Name;
5282         if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy))
5283           Name = TypedefTy->getDecl()->getName();
5284         else
5285           Name = CastTyName;
5286         EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
5287                                << Name << IntendedTy << IsEnum
5288                                << E->getSourceRange(),
5289                              E->getLocStart(), /*IsStringLocation=*/false,
5290                              SpecRange, Hints);
5291       } else {
5292         // In this case, the expression could be printed using a different
5293         // specifier, but we've decided that the specifier is probably correct
5294         // and we should cast instead. Just use the normal warning message.
5295         EmitFormatDiagnostic(
5296           S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
5297             << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum
5298             << E->getSourceRange(),
5299           E->getLocStart(), /*IsStringLocation*/false,
5300           SpecRange, Hints);
5301       }
5302     }
5303   } else {
5304     const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
5305                                                    SpecifierLen);
5306     // Since the warning for passing non-POD types to variadic functions
5307     // was deferred until now, we emit a warning for non-POD
5308     // arguments here.
5309     switch (S.isValidVarArgType(ExprTy)) {
5310     case Sema::VAK_Valid:
5311     case Sema::VAK_ValidInCXX11: {
5312       unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
5313       if (match == analyze_printf::ArgType::NoMatchPedantic) {
5314         diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
5315       }
5316 
5317       EmitFormatDiagnostic(
5318           S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context) << ExprTy
5319                         << IsEnum << CSR << E->getSourceRange(),
5320           E->getLocStart(), /*IsStringLocation*/ false, CSR);
5321       break;
5322     }
5323     case Sema::VAK_Undefined:
5324     case Sema::VAK_MSVCUndefined:
5325       EmitFormatDiagnostic(
5326         S.PDiag(diag::warn_non_pod_vararg_with_format_string)
5327           << S.getLangOpts().CPlusPlus11
5328           << ExprTy
5329           << CallType
5330           << AT.getRepresentativeTypeName(S.Context)
5331           << CSR
5332           << E->getSourceRange(),
5333         E->getLocStart(), /*IsStringLocation*/false, CSR);
5334       checkForCStrMembers(AT, E);
5335       break;
5336 
5337     case Sema::VAK_Invalid:
5338       if (ExprTy->isObjCObjectType())
5339         EmitFormatDiagnostic(
5340           S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format)
5341             << S.getLangOpts().CPlusPlus11
5342             << ExprTy
5343             << CallType
5344             << AT.getRepresentativeTypeName(S.Context)
5345             << CSR
5346             << E->getSourceRange(),
5347           E->getLocStart(), /*IsStringLocation*/false, CSR);
5348       else
5349         // FIXME: If this is an initializer list, suggest removing the braces
5350         // or inserting a cast to the target type.
5351         S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format)
5352           << isa<InitListExpr>(E) << ExprTy << CallType
5353           << AT.getRepresentativeTypeName(S.Context)
5354           << E->getSourceRange();
5355       break;
5356     }
5357 
5358     assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() &&
5359            "format string specifier index out of range");
5360     CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true;
5361   }
5362 
5363   return true;
5364 }
5365 
5366 //===--- CHECK: Scanf format string checking ------------------------------===//
5367 
5368 namespace {
5369 class CheckScanfHandler : public CheckFormatHandler {
5370 public:
CheckScanfHandler(Sema & s,const StringLiteral * fexpr,const Expr * origFormatExpr,unsigned firstDataArg,unsigned numDataArgs,const char * beg,bool hasVAListArg,ArrayRef<const Expr * > Args,unsigned formatIdx,bool inFunctionCall,Sema::VariadicCallType CallType,llvm::SmallBitVector & CheckedVarArgs,UncoveredArgHandler & UncoveredArg)5371   CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
5372                     const Expr *origFormatExpr, unsigned firstDataArg,
5373                     unsigned numDataArgs, const char *beg, bool hasVAListArg,
5374                     ArrayRef<const Expr *> Args,
5375                     unsigned formatIdx, bool inFunctionCall,
5376                     Sema::VariadicCallType CallType,
5377                     llvm::SmallBitVector &CheckedVarArgs,
5378                     UncoveredArgHandler &UncoveredArg)
5379     : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
5380                          numDataArgs, beg, hasVAListArg,
5381                          Args, formatIdx, inFunctionCall, CallType,
5382                          CheckedVarArgs, UncoveredArg)
5383   {}
5384 
5385   bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
5386                             const char *startSpecifier,
5387                             unsigned specifierLen) override;
5388 
5389   bool HandleInvalidScanfConversionSpecifier(
5390           const analyze_scanf::ScanfSpecifier &FS,
5391           const char *startSpecifier,
5392           unsigned specifierLen) override;
5393 
5394   void HandleIncompleteScanList(const char *start, const char *end) override;
5395 };
5396 } // end anonymous namespace
5397 
HandleIncompleteScanList(const char * start,const char * end)5398 void CheckScanfHandler::HandleIncompleteScanList(const char *start,
5399                                                  const char *end) {
5400   EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
5401                        getLocationOfByte(end), /*IsStringLocation*/true,
5402                        getSpecifierRange(start, end - start));
5403 }
5404 
HandleInvalidScanfConversionSpecifier(const analyze_scanf::ScanfSpecifier & FS,const char * startSpecifier,unsigned specifierLen)5405 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
5406                                         const analyze_scanf::ScanfSpecifier &FS,
5407                                         const char *startSpecifier,
5408                                         unsigned specifierLen) {
5409 
5410   const analyze_scanf::ScanfConversionSpecifier &CS =
5411     FS.getConversionSpecifier();
5412 
5413   return HandleInvalidConversionSpecifier(FS.getArgIndex(),
5414                                           getLocationOfByte(CS.getStart()),
5415                                           startSpecifier, specifierLen,
5416                                           CS.getStart(), CS.getLength());
5417 }
5418 
HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier & FS,const char * startSpecifier,unsigned specifierLen)5419 bool CheckScanfHandler::HandleScanfSpecifier(
5420                                        const analyze_scanf::ScanfSpecifier &FS,
5421                                        const char *startSpecifier,
5422                                        unsigned specifierLen) {
5423   using namespace analyze_scanf;
5424   using namespace analyze_format_string;
5425 
5426   const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
5427 
5428   // Handle case where '%' and '*' don't consume an argument.  These shouldn't
5429   // be used to decide if we are using positional arguments consistently.
5430   if (FS.consumesDataArgument()) {
5431     if (atFirstArg) {
5432       atFirstArg = false;
5433       usesPositionalArgs = FS.usesPositionalArg();
5434     }
5435     else if (usesPositionalArgs != FS.usesPositionalArg()) {
5436       HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
5437                                         startSpecifier, specifierLen);
5438       return false;
5439     }
5440   }
5441 
5442   // Check if the field with is non-zero.
5443   const OptionalAmount &Amt = FS.getFieldWidth();
5444   if (Amt.getHowSpecified() == OptionalAmount::Constant) {
5445     if (Amt.getConstantAmount() == 0) {
5446       const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
5447                                                    Amt.getConstantLength());
5448       EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
5449                            getLocationOfByte(Amt.getStart()),
5450                            /*IsStringLocation*/true, R,
5451                            FixItHint::CreateRemoval(R));
5452     }
5453   }
5454 
5455   if (!FS.consumesDataArgument()) {
5456     // FIXME: Technically specifying a precision or field width here
5457     // makes no sense.  Worth issuing a warning at some point.
5458     return true;
5459   }
5460 
5461   // Consume the argument.
5462   unsigned argIndex = FS.getArgIndex();
5463   if (argIndex < NumDataArgs) {
5464       // The check to see if the argIndex is valid will come later.
5465       // We set the bit here because we may exit early from this
5466       // function if we encounter some other error.
5467     CoveredArgs.set(argIndex);
5468   }
5469 
5470   // Check the length modifier is valid with the given conversion specifier.
5471   if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
5472     HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
5473                                 diag::warn_format_nonsensical_length);
5474   else if (!FS.hasStandardLengthModifier())
5475     HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
5476   else if (!FS.hasStandardLengthConversionCombination())
5477     HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
5478                                 diag::warn_format_non_standard_conversion_spec);
5479 
5480   if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
5481     HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
5482 
5483   // The remaining checks depend on the data arguments.
5484   if (HasVAListArg)
5485     return true;
5486 
5487   if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
5488     return false;
5489 
5490   // Check that the argument type matches the format specifier.
5491   const Expr *Ex = getDataArg(argIndex);
5492   if (!Ex)
5493     return true;
5494 
5495   const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
5496 
5497   if (!AT.isValid()) {
5498     return true;
5499   }
5500 
5501   analyze_format_string::ArgType::MatchKind match =
5502       AT.matchesType(S.Context, Ex->getType());
5503   if (match == analyze_format_string::ArgType::Match) {
5504     return true;
5505   }
5506 
5507   ScanfSpecifier fixedFS = FS;
5508   bool success = fixedFS.fixType(Ex->getType(), Ex->IgnoreImpCasts()->getType(),
5509                                  S.getLangOpts(), S.Context);
5510 
5511   unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
5512   if (match == analyze_format_string::ArgType::NoMatchPedantic) {
5513     diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
5514   }
5515 
5516   if (success) {
5517     // Get the fix string from the fixed format specifier.
5518     SmallString<128> buf;
5519     llvm::raw_svector_ostream os(buf);
5520     fixedFS.toString(os);
5521 
5522     EmitFormatDiagnostic(
5523         S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context)
5524                       << Ex->getType() << false << Ex->getSourceRange(),
5525         Ex->getLocStart(),
5526         /*IsStringLocation*/ false,
5527         getSpecifierRange(startSpecifier, specifierLen),
5528         FixItHint::CreateReplacement(
5529             getSpecifierRange(startSpecifier, specifierLen), os.str()));
5530   } else {
5531     EmitFormatDiagnostic(S.PDiag(diag)
5532                              << AT.getRepresentativeTypeName(S.Context)
5533                              << Ex->getType() << false << Ex->getSourceRange(),
5534                          Ex->getLocStart(),
5535                          /*IsStringLocation*/ false,
5536                          getSpecifierRange(startSpecifier, specifierLen));
5537   }
5538 
5539   return true;
5540 }
5541 
CheckFormatString(Sema & S,const StringLiteral * FExpr,const Expr * OrigFormatExpr,ArrayRef<const Expr * > Args,bool HasVAListArg,unsigned format_idx,unsigned firstDataArg,Sema::FormatStringType Type,bool inFunctionCall,Sema::VariadicCallType CallType,llvm::SmallBitVector & CheckedVarArgs,UncoveredArgHandler & UncoveredArg)5542 static void CheckFormatString(Sema &S, const StringLiteral *FExpr,
5543                               const Expr *OrigFormatExpr,
5544                               ArrayRef<const Expr *> Args,
5545                               bool HasVAListArg, unsigned format_idx,
5546                               unsigned firstDataArg,
5547                               Sema::FormatStringType Type,
5548                               bool inFunctionCall,
5549                               Sema::VariadicCallType CallType,
5550                               llvm::SmallBitVector &CheckedVarArgs,
5551                               UncoveredArgHandler &UncoveredArg) {
5552   // CHECK: is the format string a wide literal?
5553   if (!FExpr->isAscii() && !FExpr->isUTF8()) {
5554     CheckFormatHandler::EmitFormatDiagnostic(
5555       S, inFunctionCall, Args[format_idx],
5556       S.PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
5557       /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
5558     return;
5559   }
5560 
5561   // Str - The format string.  NOTE: this is NOT null-terminated!
5562   StringRef StrRef = FExpr->getString();
5563   const char *Str = StrRef.data();
5564   // Account for cases where the string literal is truncated in a declaration.
5565   const ConstantArrayType *T =
5566     S.Context.getAsConstantArrayType(FExpr->getType());
5567   assert(T && "String literal not of constant array type!");
5568   size_t TypeSize = T->getSize().getZExtValue();
5569   size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
5570   const unsigned numDataArgs = Args.size() - firstDataArg;
5571 
5572   // Emit a warning if the string literal is truncated and does not contain an
5573   // embedded null character.
5574   if (TypeSize <= StrRef.size() &&
5575       StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) {
5576     CheckFormatHandler::EmitFormatDiagnostic(
5577         S, inFunctionCall, Args[format_idx],
5578         S.PDiag(diag::warn_printf_format_string_not_null_terminated),
5579         FExpr->getLocStart(),
5580         /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange());
5581     return;
5582   }
5583 
5584   // CHECK: empty format string?
5585   if (StrLen == 0 && numDataArgs > 0) {
5586     CheckFormatHandler::EmitFormatDiagnostic(
5587       S, inFunctionCall, Args[format_idx],
5588       S.PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
5589       /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
5590     return;
5591   }
5592 
5593   if (Type == Sema::FST_Printf || Type == Sema::FST_NSString ||
5594       Type == Sema::FST_FreeBSDKPrintf || Type == Sema::FST_OSTrace) {
5595     CheckPrintfHandler H(S, FExpr, OrigFormatExpr, firstDataArg,
5596                          numDataArgs, (Type == Sema::FST_NSString ||
5597                                        Type == Sema::FST_OSTrace),
5598                          Str, HasVAListArg, Args, format_idx,
5599                          inFunctionCall, CallType, CheckedVarArgs,
5600                          UncoveredArg);
5601 
5602     if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
5603                                                   S.getLangOpts(),
5604                                                   S.Context.getTargetInfo(),
5605                                             Type == Sema::FST_FreeBSDKPrintf))
5606       H.DoneProcessing();
5607   } else if (Type == Sema::FST_Scanf) {
5608     CheckScanfHandler H(S, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
5609                         Str, HasVAListArg, Args, format_idx,
5610                         inFunctionCall, CallType, CheckedVarArgs,
5611                         UncoveredArg);
5612 
5613     if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
5614                                                  S.getLangOpts(),
5615                                                  S.Context.getTargetInfo()))
5616       H.DoneProcessing();
5617   } // TODO: handle other formats
5618 }
5619 
FormatStringHasSArg(const StringLiteral * FExpr)5620 bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) {
5621   // Str - The format string.  NOTE: this is NOT null-terminated!
5622   StringRef StrRef = FExpr->getString();
5623   const char *Str = StrRef.data();
5624   // Account for cases where the string literal is truncated in a declaration.
5625   const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType());
5626   assert(T && "String literal not of constant array type!");
5627   size_t TypeSize = T->getSize().getZExtValue();
5628   size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
5629   return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen,
5630                                                          getLangOpts(),
5631                                                          Context.getTargetInfo());
5632 }
5633 
5634 //===--- CHECK: Warn on use of wrong absolute value function. -------------===//
5635 
5636 // Returns the related absolute value function that is larger, of 0 if one
5637 // does not exist.
getLargerAbsoluteValueFunction(unsigned AbsFunction)5638 static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) {
5639   switch (AbsFunction) {
5640   default:
5641     return 0;
5642 
5643   case Builtin::BI__builtin_abs:
5644     return Builtin::BI__builtin_labs;
5645   case Builtin::BI__builtin_labs:
5646     return Builtin::BI__builtin_llabs;
5647   case Builtin::BI__builtin_llabs:
5648     return 0;
5649 
5650   case Builtin::BI__builtin_fabsf:
5651     return Builtin::BI__builtin_fabs;
5652   case Builtin::BI__builtin_fabs:
5653     return Builtin::BI__builtin_fabsl;
5654   case Builtin::BI__builtin_fabsl:
5655     return 0;
5656 
5657   case Builtin::BI__builtin_cabsf:
5658     return Builtin::BI__builtin_cabs;
5659   case Builtin::BI__builtin_cabs:
5660     return Builtin::BI__builtin_cabsl;
5661   case Builtin::BI__builtin_cabsl:
5662     return 0;
5663 
5664   case Builtin::BIabs:
5665     return Builtin::BIlabs;
5666   case Builtin::BIlabs:
5667     return Builtin::BIllabs;
5668   case Builtin::BIllabs:
5669     return 0;
5670 
5671   case Builtin::BIfabsf:
5672     return Builtin::BIfabs;
5673   case Builtin::BIfabs:
5674     return Builtin::BIfabsl;
5675   case Builtin::BIfabsl:
5676     return 0;
5677 
5678   case Builtin::BIcabsf:
5679    return Builtin::BIcabs;
5680   case Builtin::BIcabs:
5681     return Builtin::BIcabsl;
5682   case Builtin::BIcabsl:
5683     return 0;
5684   }
5685 }
5686 
5687 // Returns the argument type of the absolute value function.
getAbsoluteValueArgumentType(ASTContext & Context,unsigned AbsType)5688 static QualType getAbsoluteValueArgumentType(ASTContext &Context,
5689                                              unsigned AbsType) {
5690   if (AbsType == 0)
5691     return QualType();
5692 
5693   ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None;
5694   QualType BuiltinType = Context.GetBuiltinType(AbsType, Error);
5695   if (Error != ASTContext::GE_None)
5696     return QualType();
5697 
5698   const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>();
5699   if (!FT)
5700     return QualType();
5701 
5702   if (FT->getNumParams() != 1)
5703     return QualType();
5704 
5705   return FT->getParamType(0);
5706 }
5707 
5708 // Returns the best absolute value function, or zero, based on type and
5709 // current absolute value function.
getBestAbsFunction(ASTContext & Context,QualType ArgType,unsigned AbsFunctionKind)5710 static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType,
5711                                    unsigned AbsFunctionKind) {
5712   unsigned BestKind = 0;
5713   uint64_t ArgSize = Context.getTypeSize(ArgType);
5714   for (unsigned Kind = AbsFunctionKind; Kind != 0;
5715        Kind = getLargerAbsoluteValueFunction(Kind)) {
5716     QualType ParamType = getAbsoluteValueArgumentType(Context, Kind);
5717     if (Context.getTypeSize(ParamType) >= ArgSize) {
5718       if (BestKind == 0)
5719         BestKind = Kind;
5720       else if (Context.hasSameType(ParamType, ArgType)) {
5721         BestKind = Kind;
5722         break;
5723       }
5724     }
5725   }
5726   return BestKind;
5727 }
5728 
5729 enum AbsoluteValueKind {
5730   AVK_Integer,
5731   AVK_Floating,
5732   AVK_Complex
5733 };
5734 
getAbsoluteValueKind(QualType T)5735 static AbsoluteValueKind getAbsoluteValueKind(QualType T) {
5736   if (T->isIntegralOrEnumerationType())
5737     return AVK_Integer;
5738   if (T->isRealFloatingType())
5739     return AVK_Floating;
5740   if (T->isAnyComplexType())
5741     return AVK_Complex;
5742 
5743   llvm_unreachable("Type not integer, floating, or complex");
5744 }
5745 
5746 // Changes the absolute value function to a different type.  Preserves whether
5747 // the function is a builtin.
changeAbsFunction(unsigned AbsKind,AbsoluteValueKind ValueKind)5748 static unsigned changeAbsFunction(unsigned AbsKind,
5749                                   AbsoluteValueKind ValueKind) {
5750   switch (ValueKind) {
5751   case AVK_Integer:
5752     switch (AbsKind) {
5753     default:
5754       return 0;
5755     case Builtin::BI__builtin_fabsf:
5756     case Builtin::BI__builtin_fabs:
5757     case Builtin::BI__builtin_fabsl:
5758     case Builtin::BI__builtin_cabsf:
5759     case Builtin::BI__builtin_cabs:
5760     case Builtin::BI__builtin_cabsl:
5761       return Builtin::BI__builtin_abs;
5762     case Builtin::BIfabsf:
5763     case Builtin::BIfabs:
5764     case Builtin::BIfabsl:
5765     case Builtin::BIcabsf:
5766     case Builtin::BIcabs:
5767     case Builtin::BIcabsl:
5768       return Builtin::BIabs;
5769     }
5770   case AVK_Floating:
5771     switch (AbsKind) {
5772     default:
5773       return 0;
5774     case Builtin::BI__builtin_abs:
5775     case Builtin::BI__builtin_labs:
5776     case Builtin::BI__builtin_llabs:
5777     case Builtin::BI__builtin_cabsf:
5778     case Builtin::BI__builtin_cabs:
5779     case Builtin::BI__builtin_cabsl:
5780       return Builtin::BI__builtin_fabsf;
5781     case Builtin::BIabs:
5782     case Builtin::BIlabs:
5783     case Builtin::BIllabs:
5784     case Builtin::BIcabsf:
5785     case Builtin::BIcabs:
5786     case Builtin::BIcabsl:
5787       return Builtin::BIfabsf;
5788     }
5789   case AVK_Complex:
5790     switch (AbsKind) {
5791     default:
5792       return 0;
5793     case Builtin::BI__builtin_abs:
5794     case Builtin::BI__builtin_labs:
5795     case Builtin::BI__builtin_llabs:
5796     case Builtin::BI__builtin_fabsf:
5797     case Builtin::BI__builtin_fabs:
5798     case Builtin::BI__builtin_fabsl:
5799       return Builtin::BI__builtin_cabsf;
5800     case Builtin::BIabs:
5801     case Builtin::BIlabs:
5802     case Builtin::BIllabs:
5803     case Builtin::BIfabsf:
5804     case Builtin::BIfabs:
5805     case Builtin::BIfabsl:
5806       return Builtin::BIcabsf;
5807     }
5808   }
5809   llvm_unreachable("Unable to convert function");
5810 }
5811 
getAbsoluteValueFunctionKind(const FunctionDecl * FDecl)5812 static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) {
5813   const IdentifierInfo *FnInfo = FDecl->getIdentifier();
5814   if (!FnInfo)
5815     return 0;
5816 
5817   switch (FDecl->getBuiltinID()) {
5818   default:
5819     return 0;
5820   case Builtin::BI__builtin_abs:
5821   case Builtin::BI__builtin_fabs:
5822   case Builtin::BI__builtin_fabsf:
5823   case Builtin::BI__builtin_fabsl:
5824   case Builtin::BI__builtin_labs:
5825   case Builtin::BI__builtin_llabs:
5826   case Builtin::BI__builtin_cabs:
5827   case Builtin::BI__builtin_cabsf:
5828   case Builtin::BI__builtin_cabsl:
5829   case Builtin::BIabs:
5830   case Builtin::BIlabs:
5831   case Builtin::BIllabs:
5832   case Builtin::BIfabs:
5833   case Builtin::BIfabsf:
5834   case Builtin::BIfabsl:
5835   case Builtin::BIcabs:
5836   case Builtin::BIcabsf:
5837   case Builtin::BIcabsl:
5838     return FDecl->getBuiltinID();
5839   }
5840   llvm_unreachable("Unknown Builtin type");
5841 }
5842 
5843 // If the replacement is valid, emit a note with replacement function.
5844 // Additionally, suggest including the proper header if not already included.
emitReplacement(Sema & S,SourceLocation Loc,SourceRange Range,unsigned AbsKind,QualType ArgType)5845 static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range,
5846                             unsigned AbsKind, QualType ArgType) {
5847   bool EmitHeaderHint = true;
5848   const char *HeaderName = nullptr;
5849   const char *FunctionName = nullptr;
5850   if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) {
5851     FunctionName = "std::abs";
5852     if (ArgType->isIntegralOrEnumerationType()) {
5853       HeaderName = "cstdlib";
5854     } else if (ArgType->isRealFloatingType()) {
5855       HeaderName = "cmath";
5856     } else {
5857       llvm_unreachable("Invalid Type");
5858     }
5859 
5860     // Lookup all std::abs
5861     if (NamespaceDecl *Std = S.getStdNamespace()) {
5862       LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName);
5863       R.suppressDiagnostics();
5864       S.LookupQualifiedName(R, Std);
5865 
5866       for (const auto *I : R) {
5867         const FunctionDecl *FDecl = nullptr;
5868         if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) {
5869           FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl());
5870         } else {
5871           FDecl = dyn_cast<FunctionDecl>(I);
5872         }
5873         if (!FDecl)
5874           continue;
5875 
5876         // Found std::abs(), check that they are the right ones.
5877         if (FDecl->getNumParams() != 1)
5878           continue;
5879 
5880         // Check that the parameter type can handle the argument.
5881         QualType ParamType = FDecl->getParamDecl(0)->getType();
5882         if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) &&
5883             S.Context.getTypeSize(ArgType) <=
5884                 S.Context.getTypeSize(ParamType)) {
5885           // Found a function, don't need the header hint.
5886           EmitHeaderHint = false;
5887           break;
5888         }
5889       }
5890     }
5891   } else {
5892     FunctionName = S.Context.BuiltinInfo.getName(AbsKind);
5893     HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind);
5894 
5895     if (HeaderName) {
5896       DeclarationName DN(&S.Context.Idents.get(FunctionName));
5897       LookupResult R(S, DN, Loc, Sema::LookupAnyName);
5898       R.suppressDiagnostics();
5899       S.LookupName(R, S.getCurScope());
5900 
5901       if (R.isSingleResult()) {
5902         FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl());
5903         if (FD && FD->getBuiltinID() == AbsKind) {
5904           EmitHeaderHint = false;
5905         } else {
5906           return;
5907         }
5908       } else if (!R.empty()) {
5909         return;
5910       }
5911     }
5912   }
5913 
5914   S.Diag(Loc, diag::note_replace_abs_function)
5915       << FunctionName << FixItHint::CreateReplacement(Range, FunctionName);
5916 
5917   if (!HeaderName)
5918     return;
5919 
5920   if (!EmitHeaderHint)
5921     return;
5922 
5923   S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName
5924                                                     << FunctionName;
5925 }
5926 
IsFunctionStdAbs(const FunctionDecl * FDecl)5927 static bool IsFunctionStdAbs(const FunctionDecl *FDecl) {
5928   if (!FDecl)
5929     return false;
5930 
5931   if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs"))
5932     return false;
5933 
5934   const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext());
5935 
5936   while (ND && ND->isInlineNamespace()) {
5937     ND = dyn_cast<NamespaceDecl>(ND->getDeclContext());
5938   }
5939 
5940   if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std"))
5941     return false;
5942 
5943   if (!isa<TranslationUnitDecl>(ND->getDeclContext()))
5944     return false;
5945 
5946   return true;
5947 }
5948 
5949 // Warn when using the wrong abs() function.
CheckAbsoluteValueFunction(const CallExpr * Call,const FunctionDecl * FDecl,IdentifierInfo * FnInfo)5950 void Sema::CheckAbsoluteValueFunction(const CallExpr *Call,
5951                                       const FunctionDecl *FDecl,
5952                                       IdentifierInfo *FnInfo) {
5953   if (Call->getNumArgs() != 1)
5954     return;
5955 
5956   unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl);
5957   bool IsStdAbs = IsFunctionStdAbs(FDecl);
5958   if (AbsKind == 0 && !IsStdAbs)
5959     return;
5960 
5961   QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType();
5962   QualType ParamType = Call->getArg(0)->getType();
5963 
5964   // Unsigned types cannot be negative.  Suggest removing the absolute value
5965   // function call.
5966   if (ArgType->isUnsignedIntegerType()) {
5967     const char *FunctionName =
5968         IsStdAbs ? "std::abs" : Context.BuiltinInfo.getName(AbsKind);
5969     Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType;
5970     Diag(Call->getExprLoc(), diag::note_remove_abs)
5971         << FunctionName
5972         << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange());
5973     return;
5974   }
5975 
5976   // Taking the absolute value of a pointer is very suspicious, they probably
5977   // wanted to index into an array, dereference a pointer, call a function, etc.
5978   if (ArgType->isPointerType() || ArgType->canDecayToPointerType()) {
5979     unsigned DiagType = 0;
5980     if (ArgType->isFunctionType())
5981       DiagType = 1;
5982     else if (ArgType->isArrayType())
5983       DiagType = 2;
5984 
5985     Diag(Call->getExprLoc(), diag::warn_pointer_abs) << DiagType << ArgType;
5986     return;
5987   }
5988 
5989   // std::abs has overloads which prevent most of the absolute value problems
5990   // from occurring.
5991   if (IsStdAbs)
5992     return;
5993 
5994   AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType);
5995   AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType);
5996 
5997   // The argument and parameter are the same kind.  Check if they are the right
5998   // size.
5999   if (ArgValueKind == ParamValueKind) {
6000     if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType))
6001       return;
6002 
6003     unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind);
6004     Diag(Call->getExprLoc(), diag::warn_abs_too_small)
6005         << FDecl << ArgType << ParamType;
6006 
6007     if (NewAbsKind == 0)
6008       return;
6009 
6010     emitReplacement(*this, Call->getExprLoc(),
6011                     Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
6012     return;
6013   }
6014 
6015   // ArgValueKind != ParamValueKind
6016   // The wrong type of absolute value function was used.  Attempt to find the
6017   // proper one.
6018   unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind);
6019   NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind);
6020   if (NewAbsKind == 0)
6021     return;
6022 
6023   Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type)
6024       << FDecl << ParamValueKind << ArgValueKind;
6025 
6026   emitReplacement(*this, Call->getExprLoc(),
6027                   Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
6028 }
6029 
6030 //===--- CHECK: Standard memory functions ---------------------------------===//
6031 
6032 /// \brief Takes the expression passed to the size_t parameter of functions
6033 /// such as memcmp, strncat, etc and warns if it's a comparison.
6034 ///
6035 /// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`.
CheckMemorySizeofForComparison(Sema & S,const Expr * E,IdentifierInfo * FnName,SourceLocation FnLoc,SourceLocation RParenLoc)6036 static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E,
6037                                            IdentifierInfo *FnName,
6038                                            SourceLocation FnLoc,
6039                                            SourceLocation RParenLoc) {
6040   const BinaryOperator *Size = dyn_cast<BinaryOperator>(E);
6041   if (!Size)
6042     return false;
6043 
6044   // if E is binop and op is >, <, >=, <=, ==, &&, ||:
6045   if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp())
6046     return false;
6047 
6048   SourceRange SizeRange = Size->getSourceRange();
6049   S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison)
6050       << SizeRange << FnName;
6051   S.Diag(FnLoc, diag::note_memsize_comparison_paren)
6052       << FnName << FixItHint::CreateInsertion(
6053                        S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")")
6054       << FixItHint::CreateRemoval(RParenLoc);
6055   S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence)
6056       << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(")
6057       << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()),
6058                                     ")");
6059 
6060   return true;
6061 }
6062 
6063 /// \brief Determine whether the given type is or contains a dynamic class type
6064 /// (e.g., whether it has a vtable).
getContainedDynamicClass(QualType T,bool & IsContained)6065 static const CXXRecordDecl *getContainedDynamicClass(QualType T,
6066                                                      bool &IsContained) {
6067   // Look through array types while ignoring qualifiers.
6068   const Type *Ty = T->getBaseElementTypeUnsafe();
6069   IsContained = false;
6070 
6071   const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
6072   RD = RD ? RD->getDefinition() : nullptr;
6073   if (!RD || RD->isInvalidDecl())
6074     return nullptr;
6075 
6076   if (RD->isDynamicClass())
6077     return RD;
6078 
6079   // Check all the fields.  If any bases were dynamic, the class is dynamic.
6080   // It's impossible for a class to transitively contain itself by value, so
6081   // infinite recursion is impossible.
6082   for (auto *FD : RD->fields()) {
6083     bool SubContained;
6084     if (const CXXRecordDecl *ContainedRD =
6085             getContainedDynamicClass(FD->getType(), SubContained)) {
6086       IsContained = true;
6087       return ContainedRD;
6088     }
6089   }
6090 
6091   return nullptr;
6092 }
6093 
6094 /// \brief If E is a sizeof expression, returns its argument expression,
6095 /// otherwise returns NULL.
getSizeOfExprArg(const Expr * E)6096 static const Expr *getSizeOfExprArg(const Expr *E) {
6097   if (const UnaryExprOrTypeTraitExpr *SizeOf =
6098       dyn_cast<UnaryExprOrTypeTraitExpr>(E))
6099     if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
6100       return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
6101 
6102   return nullptr;
6103 }
6104 
6105 /// \brief If E is a sizeof expression, returns its argument type.
getSizeOfArgType(const Expr * E)6106 static QualType getSizeOfArgType(const Expr *E) {
6107   if (const UnaryExprOrTypeTraitExpr *SizeOf =
6108       dyn_cast<UnaryExprOrTypeTraitExpr>(E))
6109     if (SizeOf->getKind() == clang::UETT_SizeOf)
6110       return SizeOf->getTypeOfArgument();
6111 
6112   return QualType();
6113 }
6114 
6115 /// \brief Check for dangerous or invalid arguments to memset().
6116 ///
6117 /// This issues warnings on known problematic, dangerous or unspecified
6118 /// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
6119 /// function calls.
6120 ///
6121 /// \param Call The call expression to diagnose.
CheckMemaccessArguments(const CallExpr * Call,unsigned BId,IdentifierInfo * FnName)6122 void Sema::CheckMemaccessArguments(const CallExpr *Call,
6123                                    unsigned BId,
6124                                    IdentifierInfo *FnName) {
6125   assert(BId != 0);
6126 
6127   // It is possible to have a non-standard definition of memset.  Validate
6128   // we have enough arguments, and if not, abort further checking.
6129   unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
6130   if (Call->getNumArgs() < ExpectedNumArgs)
6131     return;
6132 
6133   unsigned LastArg = (BId == Builtin::BImemset ||
6134                       BId == Builtin::BIstrndup ? 1 : 2);
6135   unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
6136   const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
6137 
6138   if (CheckMemorySizeofForComparison(*this, LenExpr, FnName,
6139                                      Call->getLocStart(), Call->getRParenLoc()))
6140     return;
6141 
6142   // We have special checking when the length is a sizeof expression.
6143   QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
6144   const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
6145   llvm::FoldingSetNodeID SizeOfArgID;
6146 
6147   for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
6148     const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
6149     SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
6150 
6151     QualType DestTy = Dest->getType();
6152     QualType PointeeTy;
6153     if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
6154       PointeeTy = DestPtrTy->getPointeeType();
6155 
6156       // Never warn about void type pointers. This can be used to suppress
6157       // false positives.
6158       if (PointeeTy->isVoidType())
6159         continue;
6160 
6161       // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
6162       // actually comparing the expressions for equality. Because computing the
6163       // expression IDs can be expensive, we only do this if the diagnostic is
6164       // enabled.
6165       if (SizeOfArg &&
6166           !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess,
6167                            SizeOfArg->getExprLoc())) {
6168         // We only compute IDs for expressions if the warning is enabled, and
6169         // cache the sizeof arg's ID.
6170         if (SizeOfArgID == llvm::FoldingSetNodeID())
6171           SizeOfArg->Profile(SizeOfArgID, Context, true);
6172         llvm::FoldingSetNodeID DestID;
6173         Dest->Profile(DestID, Context, true);
6174         if (DestID == SizeOfArgID) {
6175           // TODO: For strncpy() and friends, this could suggest sizeof(dst)
6176           //       over sizeof(src) as well.
6177           unsigned ActionIdx = 0; // Default is to suggest dereferencing.
6178           StringRef ReadableName = FnName->getName();
6179 
6180           if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
6181             if (UnaryOp->getOpcode() == UO_AddrOf)
6182               ActionIdx = 1; // If its an address-of operator, just remove it.
6183           if (!PointeeTy->isIncompleteType() &&
6184               (Context.getTypeSize(PointeeTy) == Context.getCharWidth()))
6185             ActionIdx = 2; // If the pointee's size is sizeof(char),
6186                            // suggest an explicit length.
6187 
6188           // If the function is defined as a builtin macro, do not show macro
6189           // expansion.
6190           SourceLocation SL = SizeOfArg->getExprLoc();
6191           SourceRange DSR = Dest->getSourceRange();
6192           SourceRange SSR = SizeOfArg->getSourceRange();
6193           SourceManager &SM = getSourceManager();
6194 
6195           if (SM.isMacroArgExpansion(SL)) {
6196             ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
6197             SL = SM.getSpellingLoc(SL);
6198             DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
6199                              SM.getSpellingLoc(DSR.getEnd()));
6200             SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
6201                              SM.getSpellingLoc(SSR.getEnd()));
6202           }
6203 
6204           DiagRuntimeBehavior(SL, SizeOfArg,
6205                               PDiag(diag::warn_sizeof_pointer_expr_memaccess)
6206                                 << ReadableName
6207                                 << PointeeTy
6208                                 << DestTy
6209                                 << DSR
6210                                 << SSR);
6211           DiagRuntimeBehavior(SL, SizeOfArg,
6212                          PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
6213                                 << ActionIdx
6214                                 << SSR);
6215 
6216           break;
6217         }
6218       }
6219 
6220       // Also check for cases where the sizeof argument is the exact same
6221       // type as the memory argument, and where it points to a user-defined
6222       // record type.
6223       if (SizeOfArgTy != QualType()) {
6224         if (PointeeTy->isRecordType() &&
6225             Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
6226           DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
6227                               PDiag(diag::warn_sizeof_pointer_type_memaccess)
6228                                 << FnName << SizeOfArgTy << ArgIdx
6229                                 << PointeeTy << Dest->getSourceRange()
6230                                 << LenExpr->getSourceRange());
6231           break;
6232         }
6233       }
6234     } else if (DestTy->isArrayType()) {
6235       PointeeTy = DestTy;
6236     }
6237 
6238     if (PointeeTy == QualType())
6239       continue;
6240 
6241     // Always complain about dynamic classes.
6242     bool IsContained;
6243     if (const CXXRecordDecl *ContainedRD =
6244             getContainedDynamicClass(PointeeTy, IsContained)) {
6245 
6246       unsigned OperationType = 0;
6247       // "overwritten" if we're warning about the destination for any call
6248       // but memcmp; otherwise a verb appropriate to the call.
6249       if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
6250         if (BId == Builtin::BImemcpy)
6251           OperationType = 1;
6252         else if(BId == Builtin::BImemmove)
6253           OperationType = 2;
6254         else if (BId == Builtin::BImemcmp)
6255           OperationType = 3;
6256       }
6257 
6258       DiagRuntimeBehavior(
6259         Dest->getExprLoc(), Dest,
6260         PDiag(diag::warn_dyn_class_memaccess)
6261           << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
6262           << FnName << IsContained << ContainedRD << OperationType
6263           << Call->getCallee()->getSourceRange());
6264     } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
6265              BId != Builtin::BImemset)
6266       DiagRuntimeBehavior(
6267         Dest->getExprLoc(), Dest,
6268         PDiag(diag::warn_arc_object_memaccess)
6269           << ArgIdx << FnName << PointeeTy
6270           << Call->getCallee()->getSourceRange());
6271     else
6272       continue;
6273 
6274     DiagRuntimeBehavior(
6275       Dest->getExprLoc(), Dest,
6276       PDiag(diag::note_bad_memaccess_silence)
6277         << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
6278     break;
6279   }
6280 }
6281 
6282 // A little helper routine: ignore addition and subtraction of integer literals.
6283 // This intentionally does not ignore all integer constant expressions because
6284 // we don't want to remove sizeof().
ignoreLiteralAdditions(const Expr * Ex,ASTContext & Ctx)6285 static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
6286   Ex = Ex->IgnoreParenCasts();
6287 
6288   for (;;) {
6289     const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
6290     if (!BO || !BO->isAdditiveOp())
6291       break;
6292 
6293     const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
6294     const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
6295 
6296     if (isa<IntegerLiteral>(RHS))
6297       Ex = LHS;
6298     else if (isa<IntegerLiteral>(LHS))
6299       Ex = RHS;
6300     else
6301       break;
6302   }
6303 
6304   return Ex;
6305 }
6306 
isConstantSizeArrayWithMoreThanOneElement(QualType Ty,ASTContext & Context)6307 static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
6308                                                       ASTContext &Context) {
6309   // Only handle constant-sized or VLAs, but not flexible members.
6310   if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
6311     // Only issue the FIXIT for arrays of size > 1.
6312     if (CAT->getSize().getSExtValue() <= 1)
6313       return false;
6314   } else if (!Ty->isVariableArrayType()) {
6315     return false;
6316   }
6317   return true;
6318 }
6319 
6320 // Warn if the user has made the 'size' argument to strlcpy or strlcat
6321 // be the size of the source, instead of the destination.
CheckStrlcpycatArguments(const CallExpr * Call,IdentifierInfo * FnName)6322 void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
6323                                     IdentifierInfo *FnName) {
6324 
6325   // Don't crash if the user has the wrong number of arguments
6326   unsigned NumArgs = Call->getNumArgs();
6327   if ((NumArgs != 3) && (NumArgs != 4))
6328     return;
6329 
6330   const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
6331   const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
6332   const Expr *CompareWithSrc = nullptr;
6333 
6334   if (CheckMemorySizeofForComparison(*this, SizeArg, FnName,
6335                                      Call->getLocStart(), Call->getRParenLoc()))
6336     return;
6337 
6338   // Look for 'strlcpy(dst, x, sizeof(x))'
6339   if (const Expr *Ex = getSizeOfExprArg(SizeArg))
6340     CompareWithSrc = Ex;
6341   else {
6342     // Look for 'strlcpy(dst, x, strlen(x))'
6343     if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
6344       if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen &&
6345           SizeCall->getNumArgs() == 1)
6346         CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
6347     }
6348   }
6349 
6350   if (!CompareWithSrc)
6351     return;
6352 
6353   // Determine if the argument to sizeof/strlen is equal to the source
6354   // argument.  In principle there's all kinds of things you could do
6355   // here, for instance creating an == expression and evaluating it with
6356   // EvaluateAsBooleanCondition, but this uses a more direct technique:
6357   const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
6358   if (!SrcArgDRE)
6359     return;
6360 
6361   const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
6362   if (!CompareWithSrcDRE ||
6363       SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
6364     return;
6365 
6366   const Expr *OriginalSizeArg = Call->getArg(2);
6367   Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
6368     << OriginalSizeArg->getSourceRange() << FnName;
6369 
6370   // Output a FIXIT hint if the destination is an array (rather than a
6371   // pointer to an array).  This could be enhanced to handle some
6372   // pointers if we know the actual size, like if DstArg is 'array+2'
6373   // we could say 'sizeof(array)-2'.
6374   const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
6375   if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
6376     return;
6377 
6378   SmallString<128> sizeString;
6379   llvm::raw_svector_ostream OS(sizeString);
6380   OS << "sizeof(";
6381   DstArg->printPretty(OS, nullptr, getPrintingPolicy());
6382   OS << ")";
6383 
6384   Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
6385     << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
6386                                     OS.str());
6387 }
6388 
6389 /// Check if two expressions refer to the same declaration.
referToTheSameDecl(const Expr * E1,const Expr * E2)6390 static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
6391   if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
6392     if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
6393       return D1->getDecl() == D2->getDecl();
6394   return false;
6395 }
6396 
getStrlenExprArg(const Expr * E)6397 static const Expr *getStrlenExprArg(const Expr *E) {
6398   if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
6399     const FunctionDecl *FD = CE->getDirectCallee();
6400     if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
6401       return nullptr;
6402     return CE->getArg(0)->IgnoreParenCasts();
6403   }
6404   return nullptr;
6405 }
6406 
6407 // Warn on anti-patterns as the 'size' argument to strncat.
6408 // The correct size argument should look like following:
6409 //   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
CheckStrncatArguments(const CallExpr * CE,IdentifierInfo * FnName)6410 void Sema::CheckStrncatArguments(const CallExpr *CE,
6411                                  IdentifierInfo *FnName) {
6412   // Don't crash if the user has the wrong number of arguments.
6413   if (CE->getNumArgs() < 3)
6414     return;
6415   const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
6416   const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
6417   const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
6418 
6419   if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(),
6420                                      CE->getRParenLoc()))
6421     return;
6422 
6423   // Identify common expressions, which are wrongly used as the size argument
6424   // to strncat and may lead to buffer overflows.
6425   unsigned PatternType = 0;
6426   if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
6427     // - sizeof(dst)
6428     if (referToTheSameDecl(SizeOfArg, DstArg))
6429       PatternType = 1;
6430     // - sizeof(src)
6431     else if (referToTheSameDecl(SizeOfArg, SrcArg))
6432       PatternType = 2;
6433   } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
6434     if (BE->getOpcode() == BO_Sub) {
6435       const Expr *L = BE->getLHS()->IgnoreParenCasts();
6436       const Expr *R = BE->getRHS()->IgnoreParenCasts();
6437       // - sizeof(dst) - strlen(dst)
6438       if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
6439           referToTheSameDecl(DstArg, getStrlenExprArg(R)))
6440         PatternType = 1;
6441       // - sizeof(src) - (anything)
6442       else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
6443         PatternType = 2;
6444     }
6445   }
6446 
6447   if (PatternType == 0)
6448     return;
6449 
6450   // Generate the diagnostic.
6451   SourceLocation SL = LenArg->getLocStart();
6452   SourceRange SR = LenArg->getSourceRange();
6453   SourceManager &SM = getSourceManager();
6454 
6455   // If the function is defined as a builtin macro, do not show macro expansion.
6456   if (SM.isMacroArgExpansion(SL)) {
6457     SL = SM.getSpellingLoc(SL);
6458     SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
6459                      SM.getSpellingLoc(SR.getEnd()));
6460   }
6461 
6462   // Check if the destination is an array (rather than a pointer to an array).
6463   QualType DstTy = DstArg->getType();
6464   bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
6465                                                                     Context);
6466   if (!isKnownSizeArray) {
6467     if (PatternType == 1)
6468       Diag(SL, diag::warn_strncat_wrong_size) << SR;
6469     else
6470       Diag(SL, diag::warn_strncat_src_size) << SR;
6471     return;
6472   }
6473 
6474   if (PatternType == 1)
6475     Diag(SL, diag::warn_strncat_large_size) << SR;
6476   else
6477     Diag(SL, diag::warn_strncat_src_size) << SR;
6478 
6479   SmallString<128> sizeString;
6480   llvm::raw_svector_ostream OS(sizeString);
6481   OS << "sizeof(";
6482   DstArg->printPretty(OS, nullptr, getPrintingPolicy());
6483   OS << ") - ";
6484   OS << "strlen(";
6485   DstArg->printPretty(OS, nullptr, getPrintingPolicy());
6486   OS << ") - 1";
6487 
6488   Diag(SL, diag::note_strncat_wrong_size)
6489     << FixItHint::CreateReplacement(SR, OS.str());
6490 }
6491 
6492 //===--- CHECK: Return Address of Stack Variable --------------------------===//
6493 
6494 static const Expr *EvalVal(const Expr *E,
6495                            SmallVectorImpl<const DeclRefExpr *> &refVars,
6496                            const Decl *ParentDecl);
6497 static const Expr *EvalAddr(const Expr *E,
6498                             SmallVectorImpl<const DeclRefExpr *> &refVars,
6499                             const Decl *ParentDecl);
6500 
6501 /// CheckReturnStackAddr - Check if a return statement returns the address
6502 ///   of a stack variable.
6503 static void
CheckReturnStackAddr(Sema & S,Expr * RetValExp,QualType lhsType,SourceLocation ReturnLoc)6504 CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
6505                      SourceLocation ReturnLoc) {
6506 
6507   const Expr *stackE = nullptr;
6508   SmallVector<const DeclRefExpr *, 8> refVars;
6509 
6510   // Perform checking for returned stack addresses, local blocks,
6511   // label addresses or references to temporaries.
6512   if (lhsType->isPointerType() ||
6513       (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
6514     stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr);
6515   } else if (lhsType->isReferenceType()) {
6516     stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr);
6517   }
6518 
6519   if (!stackE)
6520     return; // Nothing suspicious was found.
6521 
6522   SourceLocation diagLoc;
6523   SourceRange diagRange;
6524   if (refVars.empty()) {
6525     diagLoc = stackE->getLocStart();
6526     diagRange = stackE->getSourceRange();
6527   } else {
6528     // We followed through a reference variable. 'stackE' contains the
6529     // problematic expression but we will warn at the return statement pointing
6530     // at the reference variable. We will later display the "trail" of
6531     // reference variables using notes.
6532     diagLoc = refVars[0]->getLocStart();
6533     diagRange = refVars[0]->getSourceRange();
6534   }
6535 
6536   if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) {
6537     // address of local var
6538     S.Diag(diagLoc, diag::warn_ret_stack_addr_ref) << lhsType->isReferenceType()
6539      << DR->getDecl()->getDeclName() << diagRange;
6540   } else if (isa<BlockExpr>(stackE)) { // local block.
6541     S.Diag(diagLoc, diag::err_ret_local_block) << diagRange;
6542   } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
6543     S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
6544   } else { // local temporary.
6545     S.Diag(diagLoc, diag::warn_ret_local_temp_addr_ref)
6546      << lhsType->isReferenceType() << diagRange;
6547   }
6548 
6549   // Display the "trail" of reference variables that we followed until we
6550   // found the problematic expression using notes.
6551   for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
6552     const VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
6553     // If this var binds to another reference var, show the range of the next
6554     // var, otherwise the var binds to the problematic expression, in which case
6555     // show the range of the expression.
6556     SourceRange range = (i < e - 1) ? refVars[i + 1]->getSourceRange()
6557                                     : stackE->getSourceRange();
6558     S.Diag(VD->getLocation(), diag::note_ref_var_local_bind)
6559         << VD->getDeclName() << range;
6560   }
6561 }
6562 
6563 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
6564 ///  check if the expression in a return statement evaluates to an address
6565 ///  to a location on the stack, a local block, an address of a label, or a
6566 ///  reference to local temporary. The recursion is used to traverse the
6567 ///  AST of the return expression, with recursion backtracking when we
6568 ///  encounter a subexpression that (1) clearly does not lead to one of the
6569 ///  above problematic expressions (2) is something we cannot determine leads to
6570 ///  a problematic expression based on such local checking.
6571 ///
6572 ///  Both EvalAddr and EvalVal follow through reference variables to evaluate
6573 ///  the expression that they point to. Such variables are added to the
6574 ///  'refVars' vector so that we know what the reference variable "trail" was.
6575 ///
6576 ///  EvalAddr processes expressions that are pointers that are used as
6577 ///  references (and not L-values).  EvalVal handles all other values.
6578 ///  At the base case of the recursion is a check for the above problematic
6579 ///  expressions.
6580 ///
6581 ///  This implementation handles:
6582 ///
6583 ///   * pointer-to-pointer casts
6584 ///   * implicit conversions from array references to pointers
6585 ///   * taking the address of fields
6586 ///   * arbitrary interplay between "&" and "*" operators
6587 ///   * pointer arithmetic from an address of a stack variable
6588 ///   * taking the address of an array element where the array is on the stack
EvalAddr(const Expr * E,SmallVectorImpl<const DeclRefExpr * > & refVars,const Decl * ParentDecl)6589 static const Expr *EvalAddr(const Expr *E,
6590                             SmallVectorImpl<const DeclRefExpr *> &refVars,
6591                             const Decl *ParentDecl) {
6592   if (E->isTypeDependent())
6593     return nullptr;
6594 
6595   // We should only be called for evaluating pointer expressions.
6596   assert((E->getType()->isAnyPointerType() ||
6597           E->getType()->isBlockPointerType() ||
6598           E->getType()->isObjCQualifiedIdType()) &&
6599          "EvalAddr only works on pointers");
6600 
6601   E = E->IgnoreParens();
6602 
6603   // Our "symbolic interpreter" is just a dispatch off the currently
6604   // viewed AST node.  We then recursively traverse the AST by calling
6605   // EvalAddr and EvalVal appropriately.
6606   switch (E->getStmtClass()) {
6607   case Stmt::DeclRefExprClass: {
6608     const DeclRefExpr *DR = cast<DeclRefExpr>(E);
6609 
6610     // If we leave the immediate function, the lifetime isn't about to end.
6611     if (DR->refersToEnclosingVariableOrCapture())
6612       return nullptr;
6613 
6614     if (const VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
6615       // If this is a reference variable, follow through to the expression that
6616       // it points to.
6617       if (V->hasLocalStorage() &&
6618           V->getType()->isReferenceType() && V->hasInit()) {
6619         // Add the reference variable to the "trail".
6620         refVars.push_back(DR);
6621         return EvalAddr(V->getInit(), refVars, ParentDecl);
6622       }
6623 
6624     return nullptr;
6625   }
6626 
6627   case Stmt::UnaryOperatorClass: {
6628     // The only unary operator that make sense to handle here
6629     // is AddrOf.  All others don't make sense as pointers.
6630     const UnaryOperator *U = cast<UnaryOperator>(E);
6631 
6632     if (U->getOpcode() == UO_AddrOf)
6633       return EvalVal(U->getSubExpr(), refVars, ParentDecl);
6634     return nullptr;
6635   }
6636 
6637   case Stmt::BinaryOperatorClass: {
6638     // Handle pointer arithmetic.  All other binary operators are not valid
6639     // in this context.
6640     const BinaryOperator *B = cast<BinaryOperator>(E);
6641     BinaryOperatorKind op = B->getOpcode();
6642 
6643     if (op != BO_Add && op != BO_Sub)
6644       return nullptr;
6645 
6646     const Expr *Base = B->getLHS();
6647 
6648     // Determine which argument is the real pointer base.  It could be
6649     // the RHS argument instead of the LHS.
6650     if (!Base->getType()->isPointerType())
6651       Base = B->getRHS();
6652 
6653     assert(Base->getType()->isPointerType());
6654     return EvalAddr(Base, refVars, ParentDecl);
6655   }
6656 
6657   // For conditional operators we need to see if either the LHS or RHS are
6658   // valid DeclRefExpr*s.  If one of them is valid, we return it.
6659   case Stmt::ConditionalOperatorClass: {
6660     const ConditionalOperator *C = cast<ConditionalOperator>(E);
6661 
6662     // Handle the GNU extension for missing LHS.
6663     // FIXME: That isn't a ConditionalOperator, so doesn't get here.
6664     if (const Expr *LHSExpr = C->getLHS()) {
6665       // In C++, we can have a throw-expression, which has 'void' type.
6666       if (!LHSExpr->getType()->isVoidType())
6667         if (const Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl))
6668           return LHS;
6669     }
6670 
6671     // In C++, we can have a throw-expression, which has 'void' type.
6672     if (C->getRHS()->getType()->isVoidType())
6673       return nullptr;
6674 
6675     return EvalAddr(C->getRHS(), refVars, ParentDecl);
6676   }
6677 
6678   case Stmt::BlockExprClass:
6679     if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
6680       return E; // local block.
6681     return nullptr;
6682 
6683   case Stmt::AddrLabelExprClass:
6684     return E; // address of label.
6685 
6686   case Stmt::ExprWithCleanupsClass:
6687     return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
6688                     ParentDecl);
6689 
6690   // For casts, we need to handle conversions from arrays to
6691   // pointer values, and pointer-to-pointer conversions.
6692   case Stmt::ImplicitCastExprClass:
6693   case Stmt::CStyleCastExprClass:
6694   case Stmt::CXXFunctionalCastExprClass:
6695   case Stmt::ObjCBridgedCastExprClass:
6696   case Stmt::CXXStaticCastExprClass:
6697   case Stmt::CXXDynamicCastExprClass:
6698   case Stmt::CXXConstCastExprClass:
6699   case Stmt::CXXReinterpretCastExprClass: {
6700     const Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
6701     switch (cast<CastExpr>(E)->getCastKind()) {
6702     case CK_LValueToRValue:
6703     case CK_NoOp:
6704     case CK_BaseToDerived:
6705     case CK_DerivedToBase:
6706     case CK_UncheckedDerivedToBase:
6707     case CK_Dynamic:
6708     case CK_CPointerToObjCPointerCast:
6709     case CK_BlockPointerToObjCPointerCast:
6710     case CK_AnyPointerToBlockPointerCast:
6711       return EvalAddr(SubExpr, refVars, ParentDecl);
6712 
6713     case CK_ArrayToPointerDecay:
6714       return EvalVal(SubExpr, refVars, ParentDecl);
6715 
6716     case CK_BitCast:
6717       if (SubExpr->getType()->isAnyPointerType() ||
6718           SubExpr->getType()->isBlockPointerType() ||
6719           SubExpr->getType()->isObjCQualifiedIdType())
6720         return EvalAddr(SubExpr, refVars, ParentDecl);
6721       else
6722         return nullptr;
6723 
6724     default:
6725       return nullptr;
6726     }
6727   }
6728 
6729   case Stmt::MaterializeTemporaryExprClass:
6730     if (const Expr *Result =
6731             EvalAddr(cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
6732                      refVars, ParentDecl))
6733       return Result;
6734     return E;
6735 
6736   // Everything else: we simply don't reason about them.
6737   default:
6738     return nullptr;
6739   }
6740 }
6741 
6742 ///  EvalVal - This function is complements EvalAddr in the mutual recursion.
6743 ///   See the comments for EvalAddr for more details.
EvalVal(const Expr * E,SmallVectorImpl<const DeclRefExpr * > & refVars,const Decl * ParentDecl)6744 static const Expr *EvalVal(const Expr *E,
6745                            SmallVectorImpl<const DeclRefExpr *> &refVars,
6746                            const Decl *ParentDecl) {
6747   do {
6748     // We should only be called for evaluating non-pointer expressions, or
6749     // expressions with a pointer type that are not used as references but
6750     // instead
6751     // are l-values (e.g., DeclRefExpr with a pointer type).
6752 
6753     // Our "symbolic interpreter" is just a dispatch off the currently
6754     // viewed AST node.  We then recursively traverse the AST by calling
6755     // EvalAddr and EvalVal appropriately.
6756 
6757     E = E->IgnoreParens();
6758     switch (E->getStmtClass()) {
6759     case Stmt::ImplicitCastExprClass: {
6760       const ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
6761       if (IE->getValueKind() == VK_LValue) {
6762         E = IE->getSubExpr();
6763         continue;
6764       }
6765       return nullptr;
6766     }
6767 
6768     case Stmt::ExprWithCleanupsClass:
6769       return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
6770                      ParentDecl);
6771 
6772     case Stmt::DeclRefExprClass: {
6773       // When we hit a DeclRefExpr we are looking at code that refers to a
6774       // variable's name. If it's not a reference variable we check if it has
6775       // local storage within the function, and if so, return the expression.
6776       const DeclRefExpr *DR = cast<DeclRefExpr>(E);
6777 
6778       // If we leave the immediate function, the lifetime isn't about to end.
6779       if (DR->refersToEnclosingVariableOrCapture())
6780         return nullptr;
6781 
6782       if (const VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
6783         // Check if it refers to itself, e.g. "int& i = i;".
6784         if (V == ParentDecl)
6785           return DR;
6786 
6787         if (V->hasLocalStorage()) {
6788           if (!V->getType()->isReferenceType())
6789             return DR;
6790 
6791           // Reference variable, follow through to the expression that
6792           // it points to.
6793           if (V->hasInit()) {
6794             // Add the reference variable to the "trail".
6795             refVars.push_back(DR);
6796             return EvalVal(V->getInit(), refVars, V);
6797           }
6798         }
6799       }
6800 
6801       return nullptr;
6802     }
6803 
6804     case Stmt::UnaryOperatorClass: {
6805       // The only unary operator that make sense to handle here
6806       // is Deref.  All others don't resolve to a "name."  This includes
6807       // handling all sorts of rvalues passed to a unary operator.
6808       const UnaryOperator *U = cast<UnaryOperator>(E);
6809 
6810       if (U->getOpcode() == UO_Deref)
6811         return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
6812 
6813       return nullptr;
6814     }
6815 
6816     case Stmt::ArraySubscriptExprClass: {
6817       // Array subscripts are potential references to data on the stack.  We
6818       // retrieve the DeclRefExpr* for the array variable if it indeed
6819       // has local storage.
6820       const auto *ASE = cast<ArraySubscriptExpr>(E);
6821       if (ASE->isTypeDependent())
6822         return nullptr;
6823       return EvalAddr(ASE->getBase(), refVars, ParentDecl);
6824     }
6825 
6826     case Stmt::OMPArraySectionExprClass: {
6827       return EvalAddr(cast<OMPArraySectionExpr>(E)->getBase(), refVars,
6828                       ParentDecl);
6829     }
6830 
6831     case Stmt::ConditionalOperatorClass: {
6832       // For conditional operators we need to see if either the LHS or RHS are
6833       // non-NULL Expr's.  If one is non-NULL, we return it.
6834       const ConditionalOperator *C = cast<ConditionalOperator>(E);
6835 
6836       // Handle the GNU extension for missing LHS.
6837       if (const Expr *LHSExpr = C->getLHS()) {
6838         // In C++, we can have a throw-expression, which has 'void' type.
6839         if (!LHSExpr->getType()->isVoidType())
6840           if (const Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl))
6841             return LHS;
6842       }
6843 
6844       // In C++, we can have a throw-expression, which has 'void' type.
6845       if (C->getRHS()->getType()->isVoidType())
6846         return nullptr;
6847 
6848       return EvalVal(C->getRHS(), refVars, ParentDecl);
6849     }
6850 
6851     // Accesses to members are potential references to data on the stack.
6852     case Stmt::MemberExprClass: {
6853       const MemberExpr *M = cast<MemberExpr>(E);
6854 
6855       // Check for indirect access.  We only want direct field accesses.
6856       if (M->isArrow())
6857         return nullptr;
6858 
6859       // Check whether the member type is itself a reference, in which case
6860       // we're not going to refer to the member, but to what the member refers
6861       // to.
6862       if (M->getMemberDecl()->getType()->isReferenceType())
6863         return nullptr;
6864 
6865       return EvalVal(M->getBase(), refVars, ParentDecl);
6866     }
6867 
6868     case Stmt::MaterializeTemporaryExprClass:
6869       if (const Expr *Result =
6870               EvalVal(cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
6871                       refVars, ParentDecl))
6872         return Result;
6873       return E;
6874 
6875     default:
6876       // Check that we don't return or take the address of a reference to a
6877       // temporary. This is only useful in C++.
6878       if (!E->isTypeDependent() && E->isRValue())
6879         return E;
6880 
6881       // Everything else: we simply don't reason about them.
6882       return nullptr;
6883     }
6884   } while (true);
6885 }
6886 
6887 void
CheckReturnValExpr(Expr * RetValExp,QualType lhsType,SourceLocation ReturnLoc,bool isObjCMethod,const AttrVec * Attrs,const FunctionDecl * FD)6888 Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
6889                          SourceLocation ReturnLoc,
6890                          bool isObjCMethod,
6891                          const AttrVec *Attrs,
6892                          const FunctionDecl *FD) {
6893   CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc);
6894 
6895   // Check if the return value is null but should not be.
6896   if (((Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs)) ||
6897        (!isObjCMethod && isNonNullType(Context, lhsType))) &&
6898       CheckNonNullExpr(*this, RetValExp))
6899     Diag(ReturnLoc, diag::warn_null_ret)
6900       << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange();
6901 
6902   // C++11 [basic.stc.dynamic.allocation]p4:
6903   //   If an allocation function declared with a non-throwing
6904   //   exception-specification fails to allocate storage, it shall return
6905   //   a null pointer. Any other allocation function that fails to allocate
6906   //   storage shall indicate failure only by throwing an exception [...]
6907   if (FD) {
6908     OverloadedOperatorKind Op = FD->getOverloadedOperator();
6909     if (Op == OO_New || Op == OO_Array_New) {
6910       const FunctionProtoType *Proto
6911         = FD->getType()->castAs<FunctionProtoType>();
6912       if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) &&
6913           CheckNonNullExpr(*this, RetValExp))
6914         Diag(ReturnLoc, diag::warn_operator_new_returns_null)
6915           << FD << getLangOpts().CPlusPlus11;
6916     }
6917   }
6918 }
6919 
6920 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
6921 
6922 /// Check for comparisons of floating point operands using != and ==.
6923 /// Issue a warning if these are no self-comparisons, as they are not likely
6924 /// to do what the programmer intended.
CheckFloatComparison(SourceLocation Loc,Expr * LHS,Expr * RHS)6925 void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
6926   Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
6927   Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
6928 
6929   // Special case: check for x == x (which is OK).
6930   // Do not emit warnings for such cases.
6931   if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
6932     if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
6933       if (DRL->getDecl() == DRR->getDecl())
6934         return;
6935 
6936   // Special case: check for comparisons against literals that can be exactly
6937   //  represented by APFloat.  In such cases, do not emit a warning.  This
6938   //  is a heuristic: often comparison against such literals are used to
6939   //  detect if a value in a variable has not changed.  This clearly can
6940   //  lead to false negatives.
6941   if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
6942     if (FLL->isExact())
6943       return;
6944   } else
6945     if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
6946       if (FLR->isExact())
6947         return;
6948 
6949   // Check for comparisons with builtin types.
6950   if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
6951     if (CL->getBuiltinCallee())
6952       return;
6953 
6954   if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
6955     if (CR->getBuiltinCallee())
6956       return;
6957 
6958   // Emit the diagnostic.
6959   Diag(Loc, diag::warn_floatingpoint_eq)
6960     << LHS->getSourceRange() << RHS->getSourceRange();
6961 }
6962 
6963 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
6964 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
6965 
6966 namespace {
6967 
6968 /// Structure recording the 'active' range of an integer-valued
6969 /// expression.
6970 struct IntRange {
6971   /// The number of bits active in the int.
6972   unsigned Width;
6973 
6974   /// True if the int is known not to have negative values.
6975   bool NonNegative;
6976 
IntRange__anon6c85a6980811::IntRange6977   IntRange(unsigned Width, bool NonNegative)
6978     : Width(Width), NonNegative(NonNegative)
6979   {}
6980 
6981   /// Returns the range of the bool type.
forBoolType__anon6c85a6980811::IntRange6982   static IntRange forBoolType() {
6983     return IntRange(1, true);
6984   }
6985 
6986   /// Returns the range of an opaque value of the given integral type.
forValueOfType__anon6c85a6980811::IntRange6987   static IntRange forValueOfType(ASTContext &C, QualType T) {
6988     return forValueOfCanonicalType(C,
6989                           T->getCanonicalTypeInternal().getTypePtr());
6990   }
6991 
6992   /// Returns the range of an opaque value of a canonical integral type.
forValueOfCanonicalType__anon6c85a6980811::IntRange6993   static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
6994     assert(T->isCanonicalUnqualified());
6995 
6996     if (const VectorType *VT = dyn_cast<VectorType>(T))
6997       T = VT->getElementType().getTypePtr();
6998     if (const ComplexType *CT = dyn_cast<ComplexType>(T))
6999       T = CT->getElementType().getTypePtr();
7000     if (const AtomicType *AT = dyn_cast<AtomicType>(T))
7001       T = AT->getValueType().getTypePtr();
7002 
7003     // For enum types, use the known bit width of the enumerators.
7004     if (const EnumType *ET = dyn_cast<EnumType>(T)) {
7005       EnumDecl *Enum = ET->getDecl();
7006       if (!Enum->isCompleteDefinition())
7007         return IntRange(C.getIntWidth(QualType(T, 0)), false);
7008 
7009       unsigned NumPositive = Enum->getNumPositiveBits();
7010       unsigned NumNegative = Enum->getNumNegativeBits();
7011 
7012       if (NumNegative == 0)
7013         return IntRange(NumPositive, true/*NonNegative*/);
7014       else
7015         return IntRange(std::max(NumPositive + 1, NumNegative),
7016                         false/*NonNegative*/);
7017     }
7018 
7019     const BuiltinType *BT = cast<BuiltinType>(T);
7020     assert(BT->isInteger());
7021 
7022     return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
7023   }
7024 
7025   /// Returns the "target" range of a canonical integral type, i.e.
7026   /// the range of values expressible in the type.
7027   ///
7028   /// This matches forValueOfCanonicalType except that enums have the
7029   /// full range of their type, not the range of their enumerators.
forTargetOfCanonicalType__anon6c85a6980811::IntRange7030   static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
7031     assert(T->isCanonicalUnqualified());
7032 
7033     if (const VectorType *VT = dyn_cast<VectorType>(T))
7034       T = VT->getElementType().getTypePtr();
7035     if (const ComplexType *CT = dyn_cast<ComplexType>(T))
7036       T = CT->getElementType().getTypePtr();
7037     if (const AtomicType *AT = dyn_cast<AtomicType>(T))
7038       T = AT->getValueType().getTypePtr();
7039     if (const EnumType *ET = dyn_cast<EnumType>(T))
7040       T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
7041 
7042     const BuiltinType *BT = cast<BuiltinType>(T);
7043     assert(BT->isInteger());
7044 
7045     return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
7046   }
7047 
7048   /// Returns the supremum of two ranges: i.e. their conservative merge.
join__anon6c85a6980811::IntRange7049   static IntRange join(IntRange L, IntRange R) {
7050     return IntRange(std::max(L.Width, R.Width),
7051                     L.NonNegative && R.NonNegative);
7052   }
7053 
7054   /// Returns the infinum of two ranges: i.e. their aggressive merge.
meet__anon6c85a6980811::IntRange7055   static IntRange meet(IntRange L, IntRange R) {
7056     return IntRange(std::min(L.Width, R.Width),
7057                     L.NonNegative || R.NonNegative);
7058   }
7059 };
7060 
GetValueRange(ASTContext & C,llvm::APSInt & value,unsigned MaxWidth)7061 IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) {
7062   if (value.isSigned() && value.isNegative())
7063     return IntRange(value.getMinSignedBits(), false);
7064 
7065   if (value.getBitWidth() > MaxWidth)
7066     value = value.trunc(MaxWidth);
7067 
7068   // isNonNegative() just checks the sign bit without considering
7069   // signedness.
7070   return IntRange(value.getActiveBits(), true);
7071 }
7072 
GetValueRange(ASTContext & C,APValue & result,QualType Ty,unsigned MaxWidth)7073 IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
7074                        unsigned MaxWidth) {
7075   if (result.isInt())
7076     return GetValueRange(C, result.getInt(), MaxWidth);
7077 
7078   if (result.isVector()) {
7079     IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
7080     for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
7081       IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
7082       R = IntRange::join(R, El);
7083     }
7084     return R;
7085   }
7086 
7087   if (result.isComplexInt()) {
7088     IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
7089     IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
7090     return IntRange::join(R, I);
7091   }
7092 
7093   // This can happen with lossless casts to intptr_t of "based" lvalues.
7094   // Assume it might use arbitrary bits.
7095   // FIXME: The only reason we need to pass the type in here is to get
7096   // the sign right on this one case.  It would be nice if APValue
7097   // preserved this.
7098   assert(result.isLValue() || result.isAddrLabelDiff());
7099   return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
7100 }
7101 
GetExprType(const Expr * E)7102 QualType GetExprType(const Expr *E) {
7103   QualType Ty = E->getType();
7104   if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>())
7105     Ty = AtomicRHS->getValueType();
7106   return Ty;
7107 }
7108 
7109 /// Pseudo-evaluate the given integer expression, estimating the
7110 /// range of values it might take.
7111 ///
7112 /// \param MaxWidth - the width to which the value will be truncated
GetExprRange(ASTContext & C,const Expr * E,unsigned MaxWidth)7113 IntRange GetExprRange(ASTContext &C, const Expr *E, unsigned MaxWidth) {
7114   E = E->IgnoreParens();
7115 
7116   // Try a full evaluation first.
7117   Expr::EvalResult result;
7118   if (E->EvaluateAsRValue(result, C))
7119     return GetValueRange(C, result.Val, GetExprType(E), MaxWidth);
7120 
7121   // I think we only want to look through implicit casts here; if the
7122   // user has an explicit widening cast, we should treat the value as
7123   // being of the new, wider type.
7124   if (const auto *CE = dyn_cast<ImplicitCastExpr>(E)) {
7125     if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
7126       return GetExprRange(C, CE->getSubExpr(), MaxWidth);
7127 
7128     IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE));
7129 
7130     bool isIntegerCast = CE->getCastKind() == CK_IntegralCast ||
7131                          CE->getCastKind() == CK_BooleanToSignedIntegral;
7132 
7133     // Assume that non-integer casts can span the full range of the type.
7134     if (!isIntegerCast)
7135       return OutputTypeRange;
7136 
7137     IntRange SubRange
7138       = GetExprRange(C, CE->getSubExpr(),
7139                      std::min(MaxWidth, OutputTypeRange.Width));
7140 
7141     // Bail out if the subexpr's range is as wide as the cast type.
7142     if (SubRange.Width >= OutputTypeRange.Width)
7143       return OutputTypeRange;
7144 
7145     // Otherwise, we take the smaller width, and we're non-negative if
7146     // either the output type or the subexpr is.
7147     return IntRange(SubRange.Width,
7148                     SubRange.NonNegative || OutputTypeRange.NonNegative);
7149   }
7150 
7151   if (const auto *CO = dyn_cast<ConditionalOperator>(E)) {
7152     // If we can fold the condition, just take that operand.
7153     bool CondResult;
7154     if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
7155       return GetExprRange(C, CondResult ? CO->getTrueExpr()
7156                                         : CO->getFalseExpr(),
7157                           MaxWidth);
7158 
7159     // Otherwise, conservatively merge.
7160     IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
7161     IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
7162     return IntRange::join(L, R);
7163   }
7164 
7165   if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
7166     switch (BO->getOpcode()) {
7167 
7168     // Boolean-valued operations are single-bit and positive.
7169     case BO_LAnd:
7170     case BO_LOr:
7171     case BO_LT:
7172     case BO_GT:
7173     case BO_LE:
7174     case BO_GE:
7175     case BO_EQ:
7176     case BO_NE:
7177       return IntRange::forBoolType();
7178 
7179     // The type of the assignments is the type of the LHS, so the RHS
7180     // is not necessarily the same type.
7181     case BO_MulAssign:
7182     case BO_DivAssign:
7183     case BO_RemAssign:
7184     case BO_AddAssign:
7185     case BO_SubAssign:
7186     case BO_XorAssign:
7187     case BO_OrAssign:
7188       // TODO: bitfields?
7189       return IntRange::forValueOfType(C, GetExprType(E));
7190 
7191     // Simple assignments just pass through the RHS, which will have
7192     // been coerced to the LHS type.
7193     case BO_Assign:
7194       // TODO: bitfields?
7195       return GetExprRange(C, BO->getRHS(), MaxWidth);
7196 
7197     // Operations with opaque sources are black-listed.
7198     case BO_PtrMemD:
7199     case BO_PtrMemI:
7200       return IntRange::forValueOfType(C, GetExprType(E));
7201 
7202     // Bitwise-and uses the *infinum* of the two source ranges.
7203     case BO_And:
7204     case BO_AndAssign:
7205       return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
7206                             GetExprRange(C, BO->getRHS(), MaxWidth));
7207 
7208     // Left shift gets black-listed based on a judgement call.
7209     case BO_Shl:
7210       // ...except that we want to treat '1 << (blah)' as logically
7211       // positive.  It's an important idiom.
7212       if (IntegerLiteral *I
7213             = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
7214         if (I->getValue() == 1) {
7215           IntRange R = IntRange::forValueOfType(C, GetExprType(E));
7216           return IntRange(R.Width, /*NonNegative*/ true);
7217         }
7218       }
7219       // fallthrough
7220 
7221     case BO_ShlAssign:
7222       return IntRange::forValueOfType(C, GetExprType(E));
7223 
7224     // Right shift by a constant can narrow its left argument.
7225     case BO_Shr:
7226     case BO_ShrAssign: {
7227       IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
7228 
7229       // If the shift amount is a positive constant, drop the width by
7230       // that much.
7231       llvm::APSInt shift;
7232       if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
7233           shift.isNonNegative()) {
7234         unsigned zext = shift.getZExtValue();
7235         if (zext >= L.Width)
7236           L.Width = (L.NonNegative ? 0 : 1);
7237         else
7238           L.Width -= zext;
7239       }
7240 
7241       return L;
7242     }
7243 
7244     // Comma acts as its right operand.
7245     case BO_Comma:
7246       return GetExprRange(C, BO->getRHS(), MaxWidth);
7247 
7248     // Black-list pointer subtractions.
7249     case BO_Sub:
7250       if (BO->getLHS()->getType()->isPointerType())
7251         return IntRange::forValueOfType(C, GetExprType(E));
7252       break;
7253 
7254     // The width of a division result is mostly determined by the size
7255     // of the LHS.
7256     case BO_Div: {
7257       // Don't 'pre-truncate' the operands.
7258       unsigned opWidth = C.getIntWidth(GetExprType(E));
7259       IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
7260 
7261       // If the divisor is constant, use that.
7262       llvm::APSInt divisor;
7263       if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
7264         unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
7265         if (log2 >= L.Width)
7266           L.Width = (L.NonNegative ? 0 : 1);
7267         else
7268           L.Width = std::min(L.Width - log2, MaxWidth);
7269         return L;
7270       }
7271 
7272       // Otherwise, just use the LHS's width.
7273       IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
7274       return IntRange(L.Width, L.NonNegative && R.NonNegative);
7275     }
7276 
7277     // The result of a remainder can't be larger than the result of
7278     // either side.
7279     case BO_Rem: {
7280       // Don't 'pre-truncate' the operands.
7281       unsigned opWidth = C.getIntWidth(GetExprType(E));
7282       IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
7283       IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
7284 
7285       IntRange meet = IntRange::meet(L, R);
7286       meet.Width = std::min(meet.Width, MaxWidth);
7287       return meet;
7288     }
7289 
7290     // The default behavior is okay for these.
7291     case BO_Mul:
7292     case BO_Add:
7293     case BO_Xor:
7294     case BO_Or:
7295       break;
7296     }
7297 
7298     // The default case is to treat the operation as if it were closed
7299     // on the narrowest type that encompasses both operands.
7300     IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
7301     IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
7302     return IntRange::join(L, R);
7303   }
7304 
7305   if (const auto *UO = dyn_cast<UnaryOperator>(E)) {
7306     switch (UO->getOpcode()) {
7307     // Boolean-valued operations are white-listed.
7308     case UO_LNot:
7309       return IntRange::forBoolType();
7310 
7311     // Operations with opaque sources are black-listed.
7312     case UO_Deref:
7313     case UO_AddrOf: // should be impossible
7314       return IntRange::forValueOfType(C, GetExprType(E));
7315 
7316     default:
7317       return GetExprRange(C, UO->getSubExpr(), MaxWidth);
7318     }
7319   }
7320 
7321   if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
7322     return GetExprRange(C, OVE->getSourceExpr(), MaxWidth);
7323 
7324   if (const auto *BitField = E->getSourceBitField())
7325     return IntRange(BitField->getBitWidthValue(C),
7326                     BitField->getType()->isUnsignedIntegerOrEnumerationType());
7327 
7328   return IntRange::forValueOfType(C, GetExprType(E));
7329 }
7330 
GetExprRange(ASTContext & C,const Expr * E)7331 IntRange GetExprRange(ASTContext &C, const Expr *E) {
7332   return GetExprRange(C, E, C.getIntWidth(GetExprType(E)));
7333 }
7334 
7335 /// Checks whether the given value, which currently has the given
7336 /// source semantics, has the same value when coerced through the
7337 /// target semantics.
IsSameFloatAfterCast(const llvm::APFloat & value,const llvm::fltSemantics & Src,const llvm::fltSemantics & Tgt)7338 bool IsSameFloatAfterCast(const llvm::APFloat &value,
7339                           const llvm::fltSemantics &Src,
7340                           const llvm::fltSemantics &Tgt) {
7341   llvm::APFloat truncated = value;
7342 
7343   bool ignored;
7344   truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
7345   truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
7346 
7347   return truncated.bitwiseIsEqual(value);
7348 }
7349 
7350 /// Checks whether the given value, which currently has the given
7351 /// source semantics, has the same value when coerced through the
7352 /// target semantics.
7353 ///
7354 /// The value might be a vector of floats (or a complex number).
IsSameFloatAfterCast(const APValue & value,const llvm::fltSemantics & Src,const llvm::fltSemantics & Tgt)7355 bool IsSameFloatAfterCast(const APValue &value,
7356                           const llvm::fltSemantics &Src,
7357                           const llvm::fltSemantics &Tgt) {
7358   if (value.isFloat())
7359     return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
7360 
7361   if (value.isVector()) {
7362     for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
7363       if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
7364         return false;
7365     return true;
7366   }
7367 
7368   assert(value.isComplexFloat());
7369   return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
7370           IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
7371 }
7372 
7373 void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
7374 
IsZero(Sema & S,Expr * E)7375 bool IsZero(Sema &S, Expr *E) {
7376   // Suppress cases where we are comparing against an enum constant.
7377   if (const DeclRefExpr *DR =
7378       dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
7379     if (isa<EnumConstantDecl>(DR->getDecl()))
7380       return false;
7381 
7382   // Suppress cases where the '0' value is expanded from a macro.
7383   if (E->getLocStart().isMacroID())
7384     return false;
7385 
7386   llvm::APSInt Value;
7387   return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
7388 }
7389 
HasEnumType(Expr * E)7390 bool HasEnumType(Expr *E) {
7391   // Strip off implicit integral promotions.
7392   while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
7393     if (ICE->getCastKind() != CK_IntegralCast &&
7394         ICE->getCastKind() != CK_NoOp)
7395       break;
7396     E = ICE->getSubExpr();
7397   }
7398 
7399   return E->getType()->isEnumeralType();
7400 }
7401 
CheckTrivialUnsignedComparison(Sema & S,BinaryOperator * E)7402 void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
7403   // Disable warning in template instantiations.
7404   if (!S.ActiveTemplateInstantiations.empty())
7405     return;
7406 
7407   BinaryOperatorKind op = E->getOpcode();
7408   if (E->isValueDependent())
7409     return;
7410 
7411   if (op == BO_LT && IsZero(S, E->getRHS())) {
7412     S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
7413       << "< 0" << "false" << HasEnumType(E->getLHS())
7414       << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
7415   } else if (op == BO_GE && IsZero(S, E->getRHS())) {
7416     S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
7417       << ">= 0" << "true" << HasEnumType(E->getLHS())
7418       << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
7419   } else if (op == BO_GT && IsZero(S, E->getLHS())) {
7420     S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
7421       << "0 >" << "false" << HasEnumType(E->getRHS())
7422       << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
7423   } else if (op == BO_LE && IsZero(S, E->getLHS())) {
7424     S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
7425       << "0 <=" << "true" << HasEnumType(E->getRHS())
7426       << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
7427   }
7428 }
7429 
DiagnoseOutOfRangeComparison(Sema & S,BinaryOperator * E,Expr * Constant,Expr * Other,const llvm::APSInt & Value,bool RhsConstant)7430 void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, Expr *Constant,
7431                                   Expr *Other, const llvm::APSInt &Value,
7432                                   bool RhsConstant) {
7433   // Disable warning in template instantiations.
7434   if (!S.ActiveTemplateInstantiations.empty())
7435     return;
7436 
7437   // TODO: Investigate using GetExprRange() to get tighter bounds
7438   // on the bit ranges.
7439   QualType OtherT = Other->getType();
7440   if (const auto *AT = OtherT->getAs<AtomicType>())
7441     OtherT = AT->getValueType();
7442   IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
7443   unsigned OtherWidth = OtherRange.Width;
7444 
7445   bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue();
7446 
7447   // 0 values are handled later by CheckTrivialUnsignedComparison().
7448   if ((Value == 0) && (!OtherIsBooleanType))
7449     return;
7450 
7451   BinaryOperatorKind op = E->getOpcode();
7452   bool IsTrue = true;
7453 
7454   // Used for diagnostic printout.
7455   enum {
7456     LiteralConstant = 0,
7457     CXXBoolLiteralTrue,
7458     CXXBoolLiteralFalse
7459   } LiteralOrBoolConstant = LiteralConstant;
7460 
7461   if (!OtherIsBooleanType) {
7462     QualType ConstantT = Constant->getType();
7463     QualType CommonT = E->getLHS()->getType();
7464 
7465     if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT))
7466       return;
7467     assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) &&
7468            "comparison with non-integer type");
7469 
7470     bool ConstantSigned = ConstantT->isSignedIntegerType();
7471     bool CommonSigned = CommonT->isSignedIntegerType();
7472 
7473     bool EqualityOnly = false;
7474 
7475     if (CommonSigned) {
7476       // The common type is signed, therefore no signed to unsigned conversion.
7477       if (!OtherRange.NonNegative) {
7478         // Check that the constant is representable in type OtherT.
7479         if (ConstantSigned) {
7480           if (OtherWidth >= Value.getMinSignedBits())
7481             return;
7482         } else { // !ConstantSigned
7483           if (OtherWidth >= Value.getActiveBits() + 1)
7484             return;
7485         }
7486       } else { // !OtherSigned
7487                // Check that the constant is representable in type OtherT.
7488         // Negative values are out of range.
7489         if (ConstantSigned) {
7490           if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits())
7491             return;
7492         } else { // !ConstantSigned
7493           if (OtherWidth >= Value.getActiveBits())
7494             return;
7495         }
7496       }
7497     } else { // !CommonSigned
7498       if (OtherRange.NonNegative) {
7499         if (OtherWidth >= Value.getActiveBits())
7500           return;
7501       } else { // OtherSigned
7502         assert(!ConstantSigned &&
7503                "Two signed types converted to unsigned types.");
7504         // Check to see if the constant is representable in OtherT.
7505         if (OtherWidth > Value.getActiveBits())
7506           return;
7507         // Check to see if the constant is equivalent to a negative value
7508         // cast to CommonT.
7509         if (S.Context.getIntWidth(ConstantT) ==
7510                 S.Context.getIntWidth(CommonT) &&
7511             Value.isNegative() && Value.getMinSignedBits() <= OtherWidth)
7512           return;
7513         // The constant value rests between values that OtherT can represent
7514         // after conversion.  Relational comparison still works, but equality
7515         // comparisons will be tautological.
7516         EqualityOnly = true;
7517       }
7518     }
7519 
7520     bool PositiveConstant = !ConstantSigned || Value.isNonNegative();
7521 
7522     if (op == BO_EQ || op == BO_NE) {
7523       IsTrue = op == BO_NE;
7524     } else if (EqualityOnly) {
7525       return;
7526     } else if (RhsConstant) {
7527       if (op == BO_GT || op == BO_GE)
7528         IsTrue = !PositiveConstant;
7529       else // op == BO_LT || op == BO_LE
7530         IsTrue = PositiveConstant;
7531     } else {
7532       if (op == BO_LT || op == BO_LE)
7533         IsTrue = !PositiveConstant;
7534       else // op == BO_GT || op == BO_GE
7535         IsTrue = PositiveConstant;
7536     }
7537   } else {
7538     // Other isKnownToHaveBooleanValue
7539     enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn };
7540     enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal };
7541     enum ConstantSide { Lhs, Rhs, SizeOfConstSides };
7542 
7543     static const struct LinkedConditions {
7544       CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal];
7545       CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal];
7546       CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal];
7547       CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal];
7548       CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal];
7549       CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal];
7550 
7551     } TruthTable = {
7552         // Constant on LHS.              | Constant on RHS.              |
7553         // LT_Zero| Zero  | One   |GT_One| LT_Zero| Zero  | One   |GT_One|
7554         { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } },
7555         { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } },
7556         { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } },
7557         { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } },
7558         { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } },
7559         { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } }
7560       };
7561 
7562     bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant);
7563 
7564     enum ConstantValue ConstVal = Zero;
7565     if (Value.isUnsigned() || Value.isNonNegative()) {
7566       if (Value == 0) {
7567         LiteralOrBoolConstant =
7568             ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant;
7569         ConstVal = Zero;
7570       } else if (Value == 1) {
7571         LiteralOrBoolConstant =
7572             ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant;
7573         ConstVal = One;
7574       } else {
7575         LiteralOrBoolConstant = LiteralConstant;
7576         ConstVal = GT_One;
7577       }
7578     } else {
7579       ConstVal = LT_Zero;
7580     }
7581 
7582     CompareBoolWithConstantResult CmpRes;
7583 
7584     switch (op) {
7585     case BO_LT:
7586       CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal];
7587       break;
7588     case BO_GT:
7589       CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal];
7590       break;
7591     case BO_LE:
7592       CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal];
7593       break;
7594     case BO_GE:
7595       CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal];
7596       break;
7597     case BO_EQ:
7598       CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal];
7599       break;
7600     case BO_NE:
7601       CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal];
7602       break;
7603     default:
7604       CmpRes = Unkwn;
7605       break;
7606     }
7607 
7608     if (CmpRes == AFals) {
7609       IsTrue = false;
7610     } else if (CmpRes == ATrue) {
7611       IsTrue = true;
7612     } else {
7613       return;
7614     }
7615   }
7616 
7617   // If this is a comparison to an enum constant, include that
7618   // constant in the diagnostic.
7619   const EnumConstantDecl *ED = nullptr;
7620   if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant))
7621     ED = dyn_cast<EnumConstantDecl>(DR->getDecl());
7622 
7623   SmallString<64> PrettySourceValue;
7624   llvm::raw_svector_ostream OS(PrettySourceValue);
7625   if (ED)
7626     OS << '\'' << *ED << "' (" << Value << ")";
7627   else
7628     OS << Value;
7629 
7630   S.DiagRuntimeBehavior(
7631     E->getOperatorLoc(), E,
7632     S.PDiag(diag::warn_out_of_range_compare)
7633         << OS.str() << LiteralOrBoolConstant
7634         << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue
7635         << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange());
7636 }
7637 
7638 /// Analyze the operands of the given comparison.  Implements the
7639 /// fallback case from AnalyzeComparison.
AnalyzeImpConvsInComparison(Sema & S,BinaryOperator * E)7640 void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
7641   AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
7642   AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
7643 }
7644 
7645 /// \brief Implements -Wsign-compare.
7646 ///
7647 /// \param E the binary operator to check for warnings
AnalyzeComparison(Sema & S,BinaryOperator * E)7648 void AnalyzeComparison(Sema &S, BinaryOperator *E) {
7649   // The type the comparison is being performed in.
7650   QualType T = E->getLHS()->getType();
7651 
7652   // Only analyze comparison operators where both sides have been converted to
7653   // the same type.
7654   if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()))
7655     return AnalyzeImpConvsInComparison(S, E);
7656 
7657   // Don't analyze value-dependent comparisons directly.
7658   if (E->isValueDependent())
7659     return AnalyzeImpConvsInComparison(S, E);
7660 
7661   Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
7662   Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
7663 
7664   bool IsComparisonConstant = false;
7665 
7666   // Check whether an integer constant comparison results in a value
7667   // of 'true' or 'false'.
7668   if (T->isIntegralType(S.Context)) {
7669     llvm::APSInt RHSValue;
7670     bool IsRHSIntegralLiteral =
7671       RHS->isIntegerConstantExpr(RHSValue, S.Context);
7672     llvm::APSInt LHSValue;
7673     bool IsLHSIntegralLiteral =
7674       LHS->isIntegerConstantExpr(LHSValue, S.Context);
7675     if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
7676         DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
7677     else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
7678       DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
7679     else
7680       IsComparisonConstant =
7681         (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
7682   } else if (!T->hasUnsignedIntegerRepresentation())
7683       IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
7684 
7685   // We don't do anything special if this isn't an unsigned integral
7686   // comparison:  we're only interested in integral comparisons, and
7687   // signed comparisons only happen in cases we don't care to warn about.
7688   //
7689   // We also don't care about value-dependent expressions or expressions
7690   // whose result is a constant.
7691   if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
7692     return AnalyzeImpConvsInComparison(S, E);
7693 
7694   // Check to see if one of the (unmodified) operands is of different
7695   // signedness.
7696   Expr *signedOperand, *unsignedOperand;
7697   if (LHS->getType()->hasSignedIntegerRepresentation()) {
7698     assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
7699            "unsigned comparison between two signed integer expressions?");
7700     signedOperand = LHS;
7701     unsignedOperand = RHS;
7702   } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
7703     signedOperand = RHS;
7704     unsignedOperand = LHS;
7705   } else {
7706     CheckTrivialUnsignedComparison(S, E);
7707     return AnalyzeImpConvsInComparison(S, E);
7708   }
7709 
7710   // Otherwise, calculate the effective range of the signed operand.
7711   IntRange signedRange = GetExprRange(S.Context, signedOperand);
7712 
7713   // Go ahead and analyze implicit conversions in the operands.  Note
7714   // that we skip the implicit conversions on both sides.
7715   AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
7716   AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
7717 
7718   // If the signed range is non-negative, -Wsign-compare won't fire,
7719   // but we should still check for comparisons which are always true
7720   // or false.
7721   if (signedRange.NonNegative)
7722     return CheckTrivialUnsignedComparison(S, E);
7723 
7724   // For (in)equality comparisons, if the unsigned operand is a
7725   // constant which cannot collide with a overflowed signed operand,
7726   // then reinterpreting the signed operand as unsigned will not
7727   // change the result of the comparison.
7728   if (E->isEqualityOp()) {
7729     unsigned comparisonWidth = S.Context.getIntWidth(T);
7730     IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
7731 
7732     // We should never be unable to prove that the unsigned operand is
7733     // non-negative.
7734     assert(unsignedRange.NonNegative && "unsigned range includes negative?");
7735 
7736     if (unsignedRange.Width < comparisonWidth)
7737       return;
7738   }
7739 
7740   S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
7741     S.PDiag(diag::warn_mixed_sign_comparison)
7742       << LHS->getType() << RHS->getType()
7743       << LHS->getSourceRange() << RHS->getSourceRange());
7744 }
7745 
7746 /// Analyzes an attempt to assign the given value to a bitfield.
7747 ///
7748 /// Returns true if there was something fishy about the attempt.
AnalyzeBitFieldAssignment(Sema & S,FieldDecl * Bitfield,Expr * Init,SourceLocation InitLoc)7749 bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
7750                                SourceLocation InitLoc) {
7751   assert(Bitfield->isBitField());
7752   if (Bitfield->isInvalidDecl())
7753     return false;
7754 
7755   // White-list bool bitfields.
7756   if (Bitfield->getType()->isBooleanType())
7757     return false;
7758 
7759   // Ignore value- or type-dependent expressions.
7760   if (Bitfield->getBitWidth()->isValueDependent() ||
7761       Bitfield->getBitWidth()->isTypeDependent() ||
7762       Init->isValueDependent() ||
7763       Init->isTypeDependent())
7764     return false;
7765 
7766   Expr *OriginalInit = Init->IgnoreParenImpCasts();
7767 
7768   llvm::APSInt Value;
7769   if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
7770     return false;
7771 
7772   unsigned OriginalWidth = Value.getBitWidth();
7773   unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
7774 
7775   if (OriginalWidth <= FieldWidth)
7776     return false;
7777 
7778   // Compute the value which the bitfield will contain.
7779   llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
7780   TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
7781 
7782   // Check whether the stored value is equal to the original value.
7783   TruncatedValue = TruncatedValue.extend(OriginalWidth);
7784   if (llvm::APSInt::isSameValue(Value, TruncatedValue))
7785     return false;
7786 
7787   // Special-case bitfields of width 1: booleans are naturally 0/1, and
7788   // therefore don't strictly fit into a signed bitfield of width 1.
7789   if (FieldWidth == 1 && Value == 1)
7790     return false;
7791 
7792   std::string PrettyValue = Value.toString(10);
7793   std::string PrettyTrunc = TruncatedValue.toString(10);
7794 
7795   S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
7796     << PrettyValue << PrettyTrunc << OriginalInit->getType()
7797     << Init->getSourceRange();
7798 
7799   return true;
7800 }
7801 
7802 /// Analyze the given simple or compound assignment for warning-worthy
7803 /// operations.
AnalyzeAssignment(Sema & S,BinaryOperator * E)7804 void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
7805   // Just recurse on the LHS.
7806   AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
7807 
7808   // We want to recurse on the RHS as normal unless we're assigning to
7809   // a bitfield.
7810   if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) {
7811     if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
7812                                   E->getOperatorLoc())) {
7813       // Recurse, ignoring any implicit conversions on the RHS.
7814       return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
7815                                         E->getOperatorLoc());
7816     }
7817   }
7818 
7819   AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
7820 }
7821 
7822 /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
DiagnoseImpCast(Sema & S,Expr * E,QualType SourceType,QualType T,SourceLocation CContext,unsigned diag,bool pruneControlFlow=false)7823 void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
7824                      SourceLocation CContext, unsigned diag,
7825                      bool pruneControlFlow = false) {
7826   if (pruneControlFlow) {
7827     S.DiagRuntimeBehavior(E->getExprLoc(), E,
7828                           S.PDiag(diag)
7829                             << SourceType << T << E->getSourceRange()
7830                             << SourceRange(CContext));
7831     return;
7832   }
7833   S.Diag(E->getExprLoc(), diag)
7834     << SourceType << T << E->getSourceRange() << SourceRange(CContext);
7835 }
7836 
7837 /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
DiagnoseImpCast(Sema & S,Expr * E,QualType T,SourceLocation CContext,unsigned diag,bool pruneControlFlow=false)7838 void DiagnoseImpCast(Sema &S, Expr *E, QualType T, SourceLocation CContext,
7839                      unsigned diag, bool pruneControlFlow = false) {
7840   DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
7841 }
7842 
7843 
7844 /// Diagnose an implicit cast from a floating point value to an integer value.
DiagnoseFloatingImpCast(Sema & S,Expr * E,QualType T,SourceLocation CContext)7845 void DiagnoseFloatingImpCast(Sema &S, Expr *E, QualType T,
7846 
7847                              SourceLocation CContext) {
7848   const bool IsBool = T->isSpecificBuiltinType(BuiltinType::Bool);
7849   const bool PruneWarnings = !S.ActiveTemplateInstantiations.empty();
7850 
7851   Expr *InnerE = E->IgnoreParenImpCasts();
7852   // We also want to warn on, e.g., "int i = -1.234"
7853   if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
7854     if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
7855       InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
7856 
7857   const bool IsLiteral =
7858       isa<FloatingLiteral>(E) || isa<FloatingLiteral>(InnerE);
7859 
7860   llvm::APFloat Value(0.0);
7861   bool IsConstant =
7862     E->EvaluateAsFloat(Value, S.Context, Expr::SE_AllowSideEffects);
7863   if (!IsConstant) {
7864     return DiagnoseImpCast(S, E, T, CContext,
7865                            diag::warn_impcast_float_integer, PruneWarnings);
7866   }
7867 
7868   bool isExact = false;
7869 
7870   llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
7871                             T->hasUnsignedIntegerRepresentation());
7872   if (Value.convertToInteger(IntegerValue, llvm::APFloat::rmTowardZero,
7873                              &isExact) == llvm::APFloat::opOK &&
7874       isExact) {
7875     if (IsLiteral) return;
7876     return DiagnoseImpCast(S, E, T, CContext, diag::warn_impcast_float_integer,
7877                            PruneWarnings);
7878   }
7879 
7880   unsigned DiagID = 0;
7881   if (IsLiteral) {
7882     // Warn on floating point literal to integer.
7883     DiagID = diag::warn_impcast_literal_float_to_integer;
7884   } else if (IntegerValue == 0) {
7885     if (Value.isZero()) {  // Skip -0.0 to 0 conversion.
7886       return DiagnoseImpCast(S, E, T, CContext,
7887                              diag::warn_impcast_float_integer, PruneWarnings);
7888     }
7889     // Warn on non-zero to zero conversion.
7890     DiagID = diag::warn_impcast_float_to_integer_zero;
7891   } else {
7892     if (IntegerValue.isUnsigned()) {
7893       if (!IntegerValue.isMaxValue()) {
7894         return DiagnoseImpCast(S, E, T, CContext,
7895                                diag::warn_impcast_float_integer, PruneWarnings);
7896       }
7897     } else {  // IntegerValue.isSigned()
7898       if (!IntegerValue.isMaxSignedValue() &&
7899           !IntegerValue.isMinSignedValue()) {
7900         return DiagnoseImpCast(S, E, T, CContext,
7901                                diag::warn_impcast_float_integer, PruneWarnings);
7902       }
7903     }
7904     // Warn on evaluatable floating point expression to integer conversion.
7905     DiagID = diag::warn_impcast_float_to_integer;
7906   }
7907 
7908   // FIXME: Force the precision of the source value down so we don't print
7909   // digits which are usually useless (we don't really care here if we
7910   // truncate a digit by accident in edge cases).  Ideally, APFloat::toString
7911   // would automatically print the shortest representation, but it's a bit
7912   // tricky to implement.
7913   SmallString<16> PrettySourceValue;
7914   unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics());
7915   precision = (precision * 59 + 195) / 196;
7916   Value.toString(PrettySourceValue, precision);
7917 
7918   SmallString<16> PrettyTargetValue;
7919   if (IsBool)
7920     PrettyTargetValue = Value.isZero() ? "false" : "true";
7921   else
7922     IntegerValue.toString(PrettyTargetValue);
7923 
7924   if (PruneWarnings) {
7925     S.DiagRuntimeBehavior(E->getExprLoc(), E,
7926                           S.PDiag(DiagID)
7927                               << E->getType() << T.getUnqualifiedType()
7928                               << PrettySourceValue << PrettyTargetValue
7929                               << E->getSourceRange() << SourceRange(CContext));
7930   } else {
7931     S.Diag(E->getExprLoc(), DiagID)
7932         << E->getType() << T.getUnqualifiedType() << PrettySourceValue
7933         << PrettyTargetValue << E->getSourceRange() << SourceRange(CContext);
7934   }
7935 }
7936 
PrettyPrintInRange(const llvm::APSInt & Value,IntRange Range)7937 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
7938   if (!Range.Width) return "0";
7939 
7940   llvm::APSInt ValueInRange = Value;
7941   ValueInRange.setIsSigned(!Range.NonNegative);
7942   ValueInRange = ValueInRange.trunc(Range.Width);
7943   return ValueInRange.toString(10);
7944 }
7945 
IsImplicitBoolFloatConversion(Sema & S,Expr * Ex,bool ToBool)7946 bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
7947   if (!isa<ImplicitCastExpr>(Ex))
7948     return false;
7949 
7950   Expr *InnerE = Ex->IgnoreParenImpCasts();
7951   const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
7952   const Type *Source =
7953     S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
7954   if (Target->isDependentType())
7955     return false;
7956 
7957   const BuiltinType *FloatCandidateBT =
7958     dyn_cast<BuiltinType>(ToBool ? Source : Target);
7959   const Type *BoolCandidateType = ToBool ? Target : Source;
7960 
7961   return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
7962           FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
7963 }
7964 
CheckImplicitArgumentConversions(Sema & S,CallExpr * TheCall,SourceLocation CC)7965 void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
7966                                       SourceLocation CC) {
7967   unsigned NumArgs = TheCall->getNumArgs();
7968   for (unsigned i = 0; i < NumArgs; ++i) {
7969     Expr *CurrA = TheCall->getArg(i);
7970     if (!IsImplicitBoolFloatConversion(S, CurrA, true))
7971       continue;
7972 
7973     bool IsSwapped = ((i > 0) &&
7974         IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
7975     IsSwapped |= ((i < (NumArgs - 1)) &&
7976         IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
7977     if (IsSwapped) {
7978       // Warn on this floating-point to bool conversion.
7979       DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
7980                       CurrA->getType(), CC,
7981                       diag::warn_impcast_floating_point_to_bool);
7982     }
7983   }
7984 }
7985 
DiagnoseNullConversion(Sema & S,Expr * E,QualType T,SourceLocation CC)7986 void DiagnoseNullConversion(Sema &S, Expr *E, QualType T, SourceLocation CC) {
7987   if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer,
7988                         E->getExprLoc()))
7989     return;
7990 
7991   // Don't warn on functions which have return type nullptr_t.
7992   if (isa<CallExpr>(E))
7993     return;
7994 
7995   // Check for NULL (GNUNull) or nullptr (CXX11_nullptr).
7996   const Expr::NullPointerConstantKind NullKind =
7997       E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull);
7998   if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr)
7999     return;
8000 
8001   // Return if target type is a safe conversion.
8002   if (T->isAnyPointerType() || T->isBlockPointerType() ||
8003       T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType())
8004     return;
8005 
8006   SourceLocation Loc = E->getSourceRange().getBegin();
8007 
8008   // Venture through the macro stacks to get to the source of macro arguments.
8009   // The new location is a better location than the complete location that was
8010   // passed in.
8011   while (S.SourceMgr.isMacroArgExpansion(Loc))
8012     Loc = S.SourceMgr.getImmediateMacroCallerLoc(Loc);
8013 
8014   while (S.SourceMgr.isMacroArgExpansion(CC))
8015     CC = S.SourceMgr.getImmediateMacroCallerLoc(CC);
8016 
8017   // __null is usually wrapped in a macro.  Go up a macro if that is the case.
8018   if (NullKind == Expr::NPCK_GNUNull && Loc.isMacroID()) {
8019     StringRef MacroName = Lexer::getImmediateMacroNameForDiagnostics(
8020         Loc, S.SourceMgr, S.getLangOpts());
8021     if (MacroName == "NULL")
8022       Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
8023   }
8024 
8025   // Only warn if the null and context location are in the same macro expansion.
8026   if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC))
8027     return;
8028 
8029   S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
8030       << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC)
8031       << FixItHint::CreateReplacement(Loc,
8032                                       S.getFixItZeroLiteralForType(T, Loc));
8033 }
8034 
8035 void checkObjCArrayLiteral(Sema &S, QualType TargetType,
8036                            ObjCArrayLiteral *ArrayLiteral);
8037 void checkObjCDictionaryLiteral(Sema &S, QualType TargetType,
8038                                 ObjCDictionaryLiteral *DictionaryLiteral);
8039 
8040 /// Check a single element within a collection literal against the
8041 /// target element type.
checkObjCCollectionLiteralElement(Sema & S,QualType TargetElementType,Expr * Element,unsigned ElementKind)8042 void checkObjCCollectionLiteralElement(Sema &S, QualType TargetElementType,
8043                                        Expr *Element, unsigned ElementKind) {
8044   // Skip a bitcast to 'id' or qualified 'id'.
8045   if (auto ICE = dyn_cast<ImplicitCastExpr>(Element)) {
8046     if (ICE->getCastKind() == CK_BitCast &&
8047         ICE->getSubExpr()->getType()->getAs<ObjCObjectPointerType>())
8048       Element = ICE->getSubExpr();
8049   }
8050 
8051   QualType ElementType = Element->getType();
8052   ExprResult ElementResult(Element);
8053   if (ElementType->getAs<ObjCObjectPointerType>() &&
8054       S.CheckSingleAssignmentConstraints(TargetElementType,
8055                                          ElementResult,
8056                                          false, false)
8057         != Sema::Compatible) {
8058     S.Diag(Element->getLocStart(),
8059            diag::warn_objc_collection_literal_element)
8060       << ElementType << ElementKind << TargetElementType
8061       << Element->getSourceRange();
8062   }
8063 
8064   if (auto ArrayLiteral = dyn_cast<ObjCArrayLiteral>(Element))
8065     checkObjCArrayLiteral(S, TargetElementType, ArrayLiteral);
8066   else if (auto DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(Element))
8067     checkObjCDictionaryLiteral(S, TargetElementType, DictionaryLiteral);
8068 }
8069 
8070 /// Check an Objective-C array literal being converted to the given
8071 /// target type.
checkObjCArrayLiteral(Sema & S,QualType TargetType,ObjCArrayLiteral * ArrayLiteral)8072 void checkObjCArrayLiteral(Sema &S, QualType TargetType,
8073                            ObjCArrayLiteral *ArrayLiteral) {
8074   if (!S.NSArrayDecl)
8075     return;
8076 
8077   const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>();
8078   if (!TargetObjCPtr)
8079     return;
8080 
8081   if (TargetObjCPtr->isUnspecialized() ||
8082       TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl()
8083         != S.NSArrayDecl->getCanonicalDecl())
8084     return;
8085 
8086   auto TypeArgs = TargetObjCPtr->getTypeArgs();
8087   if (TypeArgs.size() != 1)
8088     return;
8089 
8090   QualType TargetElementType = TypeArgs[0];
8091   for (unsigned I = 0, N = ArrayLiteral->getNumElements(); I != N; ++I) {
8092     checkObjCCollectionLiteralElement(S, TargetElementType,
8093                                       ArrayLiteral->getElement(I),
8094                                       0);
8095   }
8096 }
8097 
8098 /// Check an Objective-C dictionary literal being converted to the given
8099 /// target type.
checkObjCDictionaryLiteral(Sema & S,QualType TargetType,ObjCDictionaryLiteral * DictionaryLiteral)8100 void checkObjCDictionaryLiteral(Sema &S, QualType TargetType,
8101                                 ObjCDictionaryLiteral *DictionaryLiteral) {
8102   if (!S.NSDictionaryDecl)
8103     return;
8104 
8105   const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>();
8106   if (!TargetObjCPtr)
8107     return;
8108 
8109   if (TargetObjCPtr->isUnspecialized() ||
8110       TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl()
8111         != S.NSDictionaryDecl->getCanonicalDecl())
8112     return;
8113 
8114   auto TypeArgs = TargetObjCPtr->getTypeArgs();
8115   if (TypeArgs.size() != 2)
8116     return;
8117 
8118   QualType TargetKeyType = TypeArgs[0];
8119   QualType TargetObjectType = TypeArgs[1];
8120   for (unsigned I = 0, N = DictionaryLiteral->getNumElements(); I != N; ++I) {
8121     auto Element = DictionaryLiteral->getKeyValueElement(I);
8122     checkObjCCollectionLiteralElement(S, TargetKeyType, Element.Key, 1);
8123     checkObjCCollectionLiteralElement(S, TargetObjectType, Element.Value, 2);
8124   }
8125 }
8126 
8127 // Helper function to filter out cases for constant width constant conversion.
8128 // Don't warn on char array initialization or for non-decimal values.
isSameWidthConstantConversion(Sema & S,Expr * E,QualType T,SourceLocation CC)8129 bool isSameWidthConstantConversion(Sema &S, Expr *E, QualType T,
8130                                    SourceLocation CC) {
8131   // If initializing from a constant, and the constant starts with '0',
8132   // then it is a binary, octal, or hexadecimal.  Allow these constants
8133   // to fill all the bits, even if there is a sign change.
8134   if (auto *IntLit = dyn_cast<IntegerLiteral>(E->IgnoreParenImpCasts())) {
8135     const char FirstLiteralCharacter =
8136         S.getSourceManager().getCharacterData(IntLit->getLocStart())[0];
8137     if (FirstLiteralCharacter == '0')
8138       return false;
8139   }
8140 
8141   // If the CC location points to a '{', and the type is char, then assume
8142   // assume it is an array initialization.
8143   if (CC.isValid() && T->isCharType()) {
8144     const char FirstContextCharacter =
8145         S.getSourceManager().getCharacterData(CC)[0];
8146     if (FirstContextCharacter == '{')
8147       return false;
8148   }
8149 
8150   return true;
8151 }
8152 
CheckImplicitConversion(Sema & S,Expr * E,QualType T,SourceLocation CC,bool * ICContext=nullptr)8153 void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
8154                              SourceLocation CC, bool *ICContext = nullptr) {
8155   if (E->isTypeDependent() || E->isValueDependent()) return;
8156 
8157   const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
8158   const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
8159   if (Source == Target) return;
8160   if (Target->isDependentType()) return;
8161 
8162   // If the conversion context location is invalid don't complain. We also
8163   // don't want to emit a warning if the issue occurs from the expansion of
8164   // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
8165   // delay this check as long as possible. Once we detect we are in that
8166   // scenario, we just return.
8167   if (CC.isInvalid())
8168     return;
8169 
8170   // Diagnose implicit casts to bool.
8171   if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
8172     if (isa<StringLiteral>(E))
8173       // Warn on string literal to bool.  Checks for string literals in logical
8174       // and expressions, for instance, assert(0 && "error here"), are
8175       // prevented by a check in AnalyzeImplicitConversions().
8176       return DiagnoseImpCast(S, E, T, CC,
8177                              diag::warn_impcast_string_literal_to_bool);
8178     if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) ||
8179         isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) {
8180       // This covers the literal expressions that evaluate to Objective-C
8181       // objects.
8182       return DiagnoseImpCast(S, E, T, CC,
8183                              diag::warn_impcast_objective_c_literal_to_bool);
8184     }
8185     if (Source->isPointerType() || Source->canDecayToPointerType()) {
8186       // Warn on pointer to bool conversion that is always true.
8187       S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
8188                                      SourceRange(CC));
8189     }
8190   }
8191 
8192   // Check implicit casts from Objective-C collection literals to specialized
8193   // collection types, e.g., NSArray<NSString *> *.
8194   if (auto *ArrayLiteral = dyn_cast<ObjCArrayLiteral>(E))
8195     checkObjCArrayLiteral(S, QualType(Target, 0), ArrayLiteral);
8196   else if (auto *DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(E))
8197     checkObjCDictionaryLiteral(S, QualType(Target, 0), DictionaryLiteral);
8198 
8199   // Strip vector types.
8200   if (isa<VectorType>(Source)) {
8201     if (!isa<VectorType>(Target)) {
8202       if (S.SourceMgr.isInSystemMacro(CC))
8203         return;
8204       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
8205     }
8206 
8207     // If the vector cast is cast between two vectors of the same size, it is
8208     // a bitcast, not a conversion.
8209     if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
8210       return;
8211 
8212     Source = cast<VectorType>(Source)->getElementType().getTypePtr();
8213     Target = cast<VectorType>(Target)->getElementType().getTypePtr();
8214   }
8215   if (auto VecTy = dyn_cast<VectorType>(Target))
8216     Target = VecTy->getElementType().getTypePtr();
8217 
8218   // Strip complex types.
8219   if (isa<ComplexType>(Source)) {
8220     if (!isa<ComplexType>(Target)) {
8221       if (S.SourceMgr.isInSystemMacro(CC))
8222         return;
8223 
8224       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
8225     }
8226 
8227     Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
8228     Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
8229   }
8230 
8231   const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
8232   const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
8233 
8234   // If the source is floating point...
8235   if (SourceBT && SourceBT->isFloatingPoint()) {
8236     // ...and the target is floating point...
8237     if (TargetBT && TargetBT->isFloatingPoint()) {
8238       // ...then warn if we're dropping FP rank.
8239 
8240       // Builtin FP kinds are ordered by increasing FP rank.
8241       if (SourceBT->getKind() > TargetBT->getKind()) {
8242         // Don't warn about float constants that are precisely
8243         // representable in the target type.
8244         Expr::EvalResult result;
8245         if (E->EvaluateAsRValue(result, S.Context)) {
8246           // Value might be a float, a float vector, or a float complex.
8247           if (IsSameFloatAfterCast(result.Val,
8248                    S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
8249                    S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
8250             return;
8251         }
8252 
8253         if (S.SourceMgr.isInSystemMacro(CC))
8254           return;
8255 
8256         DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
8257       }
8258       // ... or possibly if we're increasing rank, too
8259       else if (TargetBT->getKind() > SourceBT->getKind()) {
8260         if (S.SourceMgr.isInSystemMacro(CC))
8261           return;
8262 
8263         DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_double_promotion);
8264       }
8265       return;
8266     }
8267 
8268     // If the target is integral, always warn.
8269     if (TargetBT && TargetBT->isInteger()) {
8270       if (S.SourceMgr.isInSystemMacro(CC))
8271         return;
8272 
8273       DiagnoseFloatingImpCast(S, E, T, CC);
8274     }
8275 
8276     // Detect the case where a call result is converted from floating-point to
8277     // to bool, and the final argument to the call is converted from bool, to
8278     // discover this typo:
8279     //
8280     //    bool b = fabs(x < 1.0);  // should be "bool b = fabs(x) < 1.0;"
8281     //
8282     // FIXME: This is an incredibly special case; is there some more general
8283     // way to detect this class of misplaced-parentheses bug?
8284     if (Target->isBooleanType() && isa<CallExpr>(E)) {
8285       // Check last argument of function call to see if it is an
8286       // implicit cast from a type matching the type the result
8287       // is being cast to.
8288       CallExpr *CEx = cast<CallExpr>(E);
8289       if (unsigned NumArgs = CEx->getNumArgs()) {
8290         Expr *LastA = CEx->getArg(NumArgs - 1);
8291         Expr *InnerE = LastA->IgnoreParenImpCasts();
8292         if (isa<ImplicitCastExpr>(LastA) &&
8293             InnerE->getType()->isBooleanType()) {
8294           // Warn on this floating-point to bool conversion
8295           DiagnoseImpCast(S, E, T, CC,
8296                           diag::warn_impcast_floating_point_to_bool);
8297         }
8298       }
8299     }
8300     return;
8301   }
8302 
8303   DiagnoseNullConversion(S, E, T, CC);
8304 
8305   if (!Source->isIntegerType() || !Target->isIntegerType())
8306     return;
8307 
8308   // TODO: remove this early return once the false positives for constant->bool
8309   // in templates, macros, etc, are reduced or removed.
8310   if (Target->isSpecificBuiltinType(BuiltinType::Bool))
8311     return;
8312 
8313   IntRange SourceRange = GetExprRange(S.Context, E);
8314   IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
8315 
8316   if (SourceRange.Width > TargetRange.Width) {
8317     // If the source is a constant, use a default-on diagnostic.
8318     // TODO: this should happen for bitfield stores, too.
8319     llvm::APSInt Value(32);
8320     if (E->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) {
8321       if (S.SourceMgr.isInSystemMacro(CC))
8322         return;
8323 
8324       std::string PrettySourceValue = Value.toString(10);
8325       std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
8326 
8327       S.DiagRuntimeBehavior(E->getExprLoc(), E,
8328         S.PDiag(diag::warn_impcast_integer_precision_constant)
8329             << PrettySourceValue << PrettyTargetValue
8330             << E->getType() << T << E->getSourceRange()
8331             << clang::SourceRange(CC));
8332       return;
8333     }
8334 
8335     // People want to build with -Wshorten-64-to-32 and not -Wconversion.
8336     if (S.SourceMgr.isInSystemMacro(CC))
8337       return;
8338 
8339     if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
8340       return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
8341                              /* pruneControlFlow */ true);
8342     return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
8343   }
8344 
8345   if (TargetRange.Width == SourceRange.Width && !TargetRange.NonNegative &&
8346       SourceRange.NonNegative && Source->isSignedIntegerType()) {
8347     // Warn when doing a signed to signed conversion, warn if the positive
8348     // source value is exactly the width of the target type, which will
8349     // cause a negative value to be stored.
8350 
8351     llvm::APSInt Value;
8352     if (E->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects) &&
8353         !S.SourceMgr.isInSystemMacro(CC)) {
8354       if (isSameWidthConstantConversion(S, E, T, CC)) {
8355         std::string PrettySourceValue = Value.toString(10);
8356         std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
8357 
8358         S.DiagRuntimeBehavior(
8359             E->getExprLoc(), E,
8360             S.PDiag(diag::warn_impcast_integer_precision_constant)
8361                 << PrettySourceValue << PrettyTargetValue << E->getType() << T
8362                 << E->getSourceRange() << clang::SourceRange(CC));
8363         return;
8364       }
8365     }
8366 
8367     // Fall through for non-constants to give a sign conversion warning.
8368   }
8369 
8370   if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
8371       (!TargetRange.NonNegative && SourceRange.NonNegative &&
8372        SourceRange.Width == TargetRange.Width)) {
8373     if (S.SourceMgr.isInSystemMacro(CC))
8374       return;
8375 
8376     unsigned DiagID = diag::warn_impcast_integer_sign;
8377 
8378     // Traditionally, gcc has warned about this under -Wsign-compare.
8379     // We also want to warn about it in -Wconversion.
8380     // So if -Wconversion is off, use a completely identical diagnostic
8381     // in the sign-compare group.
8382     // The conditional-checking code will
8383     if (ICContext) {
8384       DiagID = diag::warn_impcast_integer_sign_conditional;
8385       *ICContext = true;
8386     }
8387 
8388     return DiagnoseImpCast(S, E, T, CC, DiagID);
8389   }
8390 
8391   // Diagnose conversions between different enumeration types.
8392   // In C, we pretend that the type of an EnumConstantDecl is its enumeration
8393   // type, to give us better diagnostics.
8394   QualType SourceType = E->getType();
8395   if (!S.getLangOpts().CPlusPlus) {
8396     if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
8397       if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
8398         EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
8399         SourceType = S.Context.getTypeDeclType(Enum);
8400         Source = S.Context.getCanonicalType(SourceType).getTypePtr();
8401       }
8402   }
8403 
8404   if (const EnumType *SourceEnum = Source->getAs<EnumType>())
8405     if (const EnumType *TargetEnum = Target->getAs<EnumType>())
8406       if (SourceEnum->getDecl()->hasNameForLinkage() &&
8407           TargetEnum->getDecl()->hasNameForLinkage() &&
8408           SourceEnum != TargetEnum) {
8409         if (S.SourceMgr.isInSystemMacro(CC))
8410           return;
8411 
8412         return DiagnoseImpCast(S, E, SourceType, T, CC,
8413                                diag::warn_impcast_different_enum_types);
8414       }
8415 }
8416 
8417 void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
8418                               SourceLocation CC, QualType T);
8419 
CheckConditionalOperand(Sema & S,Expr * E,QualType T,SourceLocation CC,bool & ICContext)8420 void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
8421                              SourceLocation CC, bool &ICContext) {
8422   E = E->IgnoreParenImpCasts();
8423 
8424   if (isa<ConditionalOperator>(E))
8425     return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
8426 
8427   AnalyzeImplicitConversions(S, E, CC);
8428   if (E->getType() != T)
8429     return CheckImplicitConversion(S, E, T, CC, &ICContext);
8430 }
8431 
CheckConditionalOperator(Sema & S,ConditionalOperator * E,SourceLocation CC,QualType T)8432 void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
8433                               SourceLocation CC, QualType T) {
8434   AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc());
8435 
8436   bool Suspicious = false;
8437   CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
8438   CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
8439 
8440   // If -Wconversion would have warned about either of the candidates
8441   // for a signedness conversion to the context type...
8442   if (!Suspicious) return;
8443 
8444   // ...but it's currently ignored...
8445   if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC))
8446     return;
8447 
8448   // ...then check whether it would have warned about either of the
8449   // candidates for a signedness conversion to the condition type.
8450   if (E->getType() == T) return;
8451 
8452   Suspicious = false;
8453   CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
8454                           E->getType(), CC, &Suspicious);
8455   if (!Suspicious)
8456     CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
8457                             E->getType(), CC, &Suspicious);
8458 }
8459 
8460 /// CheckBoolLikeConversion - Check conversion of given expression to boolean.
8461 /// Input argument E is a logical expression.
CheckBoolLikeConversion(Sema & S,Expr * E,SourceLocation CC)8462 void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) {
8463   if (S.getLangOpts().Bool)
8464     return;
8465   CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC);
8466 }
8467 
8468 /// AnalyzeImplicitConversions - Find and report any interesting
8469 /// implicit conversions in the given expression.  There are a couple
8470 /// of competing diagnostics here, -Wconversion and -Wsign-compare.
AnalyzeImplicitConversions(Sema & S,Expr * OrigE,SourceLocation CC)8471 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
8472   QualType T = OrigE->getType();
8473   Expr *E = OrigE->IgnoreParenImpCasts();
8474 
8475   if (E->isTypeDependent() || E->isValueDependent())
8476     return;
8477 
8478   // For conditional operators, we analyze the arguments as if they
8479   // were being fed directly into the output.
8480   if (isa<ConditionalOperator>(E)) {
8481     ConditionalOperator *CO = cast<ConditionalOperator>(E);
8482     CheckConditionalOperator(S, CO, CC, T);
8483     return;
8484   }
8485 
8486   // Check implicit argument conversions for function calls.
8487   if (CallExpr *Call = dyn_cast<CallExpr>(E))
8488     CheckImplicitArgumentConversions(S, Call, CC);
8489 
8490   // Go ahead and check any implicit conversions we might have skipped.
8491   // The non-canonical typecheck is just an optimization;
8492   // CheckImplicitConversion will filter out dead implicit conversions.
8493   if (E->getType() != T)
8494     CheckImplicitConversion(S, E, T, CC);
8495 
8496   // Now continue drilling into this expression.
8497 
8498   if (PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
8499     // The bound subexpressions in a PseudoObjectExpr are not reachable
8500     // as transitive children.
8501     // FIXME: Use a more uniform representation for this.
8502     for (auto *SE : POE->semantics())
8503       if (auto *OVE = dyn_cast<OpaqueValueExpr>(SE))
8504         AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC);
8505   }
8506 
8507   // Skip past explicit casts.
8508   if (isa<ExplicitCastExpr>(E)) {
8509     E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
8510     return AnalyzeImplicitConversions(S, E, CC);
8511   }
8512 
8513   if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
8514     // Do a somewhat different check with comparison operators.
8515     if (BO->isComparisonOp())
8516       return AnalyzeComparison(S, BO);
8517 
8518     // And with simple assignments.
8519     if (BO->getOpcode() == BO_Assign)
8520       return AnalyzeAssignment(S, BO);
8521   }
8522 
8523   // These break the otherwise-useful invariant below.  Fortunately,
8524   // we don't really need to recurse into them, because any internal
8525   // expressions should have been analyzed already when they were
8526   // built into statements.
8527   if (isa<StmtExpr>(E)) return;
8528 
8529   // Don't descend into unevaluated contexts.
8530   if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
8531 
8532   // Now just recurse over the expression's children.
8533   CC = E->getExprLoc();
8534   BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
8535   bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd;
8536   for (Stmt *SubStmt : E->children()) {
8537     Expr *ChildExpr = dyn_cast_or_null<Expr>(SubStmt);
8538     if (!ChildExpr)
8539       continue;
8540 
8541     if (IsLogicalAndOperator &&
8542         isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
8543       // Ignore checking string literals that are in logical and operators.
8544       // This is a common pattern for asserts.
8545       continue;
8546     AnalyzeImplicitConversions(S, ChildExpr, CC);
8547   }
8548 
8549   if (BO && BO->isLogicalOp()) {
8550     Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts();
8551     if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr))
8552       ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc());
8553 
8554     SubExpr = BO->getRHS()->IgnoreParenImpCasts();
8555     if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr))
8556       ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc());
8557   }
8558 
8559   if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E))
8560     if (U->getOpcode() == UO_LNot)
8561       ::CheckBoolLikeConversion(S, U->getSubExpr(), CC);
8562 }
8563 
8564 } // end anonymous namespace
8565 
checkOpenCLEnqueueLocalSizeArgs(Sema & S,CallExpr * TheCall,unsigned Start,unsigned End)8566 static bool checkOpenCLEnqueueLocalSizeArgs(Sema &S, CallExpr *TheCall,
8567                                             unsigned Start, unsigned End) {
8568   bool IllegalParams = false;
8569   for (unsigned I = Start; I <= End; ++I) {
8570     QualType Ty = TheCall->getArg(I)->getType();
8571     // Taking into account implicit conversions,
8572     // allow any integer within 32 bits range
8573     if (!Ty->isIntegerType() ||
8574         S.Context.getTypeSizeInChars(Ty).getQuantity() > 4) {
8575       S.Diag(TheCall->getArg(I)->getLocStart(),
8576              diag::err_opencl_enqueue_kernel_invalid_local_size_type);
8577       IllegalParams = true;
8578     }
8579     // Potentially emit standard warnings for implicit conversions if enabled
8580     // using -Wconversion.
8581     CheckImplicitConversion(S, TheCall->getArg(I), S.Context.UnsignedIntTy,
8582                             TheCall->getArg(I)->getLocStart());
8583   }
8584   return IllegalParams;
8585 }
8586 
8587 // Helper function for Sema::DiagnoseAlwaysNonNullPointer.
8588 // Returns true when emitting a warning about taking the address of a reference.
CheckForReference(Sema & SemaRef,const Expr * E,const PartialDiagnostic & PD)8589 static bool CheckForReference(Sema &SemaRef, const Expr *E,
8590                               const PartialDiagnostic &PD) {
8591   E = E->IgnoreParenImpCasts();
8592 
8593   const FunctionDecl *FD = nullptr;
8594 
8595   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
8596     if (!DRE->getDecl()->getType()->isReferenceType())
8597       return false;
8598   } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) {
8599     if (!M->getMemberDecl()->getType()->isReferenceType())
8600       return false;
8601   } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) {
8602     if (!Call->getCallReturnType(SemaRef.Context)->isReferenceType())
8603       return false;
8604     FD = Call->getDirectCallee();
8605   } else {
8606     return false;
8607   }
8608 
8609   SemaRef.Diag(E->getExprLoc(), PD);
8610 
8611   // If possible, point to location of function.
8612   if (FD) {
8613     SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD;
8614   }
8615 
8616   return true;
8617 }
8618 
8619 // Returns true if the SourceLocation is expanded from any macro body.
8620 // Returns false if the SourceLocation is invalid, is from not in a macro
8621 // expansion, or is from expanded from a top-level macro argument.
IsInAnyMacroBody(const SourceManager & SM,SourceLocation Loc)8622 static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) {
8623   if (Loc.isInvalid())
8624     return false;
8625 
8626   while (Loc.isMacroID()) {
8627     if (SM.isMacroBodyExpansion(Loc))
8628       return true;
8629     Loc = SM.getImmediateMacroCallerLoc(Loc);
8630   }
8631 
8632   return false;
8633 }
8634 
8635 /// \brief Diagnose pointers that are always non-null.
8636 /// \param E the expression containing the pointer
8637 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
8638 /// compared to a null pointer
8639 /// \param IsEqual True when the comparison is equal to a null pointer
8640 /// \param Range Extra SourceRange to highlight in the diagnostic
DiagnoseAlwaysNonNullPointer(Expr * E,Expr::NullPointerConstantKind NullKind,bool IsEqual,SourceRange Range)8641 void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
8642                                         Expr::NullPointerConstantKind NullKind,
8643                                         bool IsEqual, SourceRange Range) {
8644   if (!E)
8645     return;
8646 
8647   // Don't warn inside macros.
8648   if (E->getExprLoc().isMacroID()) {
8649     const SourceManager &SM = getSourceManager();
8650     if (IsInAnyMacroBody(SM, E->getExprLoc()) ||
8651         IsInAnyMacroBody(SM, Range.getBegin()))
8652       return;
8653   }
8654   E = E->IgnoreImpCasts();
8655 
8656   const bool IsCompare = NullKind != Expr::NPCK_NotNull;
8657 
8658   if (isa<CXXThisExpr>(E)) {
8659     unsigned DiagID = IsCompare ? diag::warn_this_null_compare
8660                                 : diag::warn_this_bool_conversion;
8661     Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual;
8662     return;
8663   }
8664 
8665   bool IsAddressOf = false;
8666 
8667   if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
8668     if (UO->getOpcode() != UO_AddrOf)
8669       return;
8670     IsAddressOf = true;
8671     E = UO->getSubExpr();
8672   }
8673 
8674   if (IsAddressOf) {
8675     unsigned DiagID = IsCompare
8676                           ? diag::warn_address_of_reference_null_compare
8677                           : diag::warn_address_of_reference_bool_conversion;
8678     PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range
8679                                          << IsEqual;
8680     if (CheckForReference(*this, E, PD)) {
8681       return;
8682     }
8683   }
8684 
8685   auto ComplainAboutNonnullParamOrCall = [&](const Attr *NonnullAttr) {
8686     bool IsParam = isa<NonNullAttr>(NonnullAttr);
8687     std::string Str;
8688     llvm::raw_string_ostream S(Str);
8689     E->printPretty(S, nullptr, getPrintingPolicy());
8690     unsigned DiagID = IsCompare ? diag::warn_nonnull_expr_compare
8691                                 : diag::warn_cast_nonnull_to_bool;
8692     Diag(E->getExprLoc(), DiagID) << IsParam << S.str()
8693       << E->getSourceRange() << Range << IsEqual;
8694     Diag(NonnullAttr->getLocation(), diag::note_declared_nonnull) << IsParam;
8695   };
8696 
8697   // If we have a CallExpr that is tagged with returns_nonnull, we can complain.
8698   if (auto *Call = dyn_cast<CallExpr>(E->IgnoreParenImpCasts())) {
8699     if (auto *Callee = Call->getDirectCallee()) {
8700       if (const Attr *A = Callee->getAttr<ReturnsNonNullAttr>()) {
8701         ComplainAboutNonnullParamOrCall(A);
8702         return;
8703       }
8704     }
8705   }
8706 
8707   // Expect to find a single Decl.  Skip anything more complicated.
8708   ValueDecl *D = nullptr;
8709   if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) {
8710     D = R->getDecl();
8711   } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
8712     D = M->getMemberDecl();
8713   }
8714 
8715   // Weak Decls can be null.
8716   if (!D || D->isWeak())
8717     return;
8718 
8719   // Check for parameter decl with nonnull attribute
8720   if (const auto* PV = dyn_cast<ParmVarDecl>(D)) {
8721     if (getCurFunction() &&
8722         !getCurFunction()->ModifiedNonNullParams.count(PV)) {
8723       if (const Attr *A = PV->getAttr<NonNullAttr>()) {
8724         ComplainAboutNonnullParamOrCall(A);
8725         return;
8726       }
8727 
8728       if (const auto *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {
8729         auto ParamIter = llvm::find(FD->parameters(), PV);
8730         assert(ParamIter != FD->param_end());
8731         unsigned ParamNo = std::distance(FD->param_begin(), ParamIter);
8732 
8733         for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) {
8734           if (!NonNull->args_size()) {
8735               ComplainAboutNonnullParamOrCall(NonNull);
8736               return;
8737           }
8738 
8739           for (unsigned ArgNo : NonNull->args()) {
8740             if (ArgNo == ParamNo) {
8741               ComplainAboutNonnullParamOrCall(NonNull);
8742               return;
8743             }
8744           }
8745         }
8746       }
8747     }
8748   }
8749 
8750   QualType T = D->getType();
8751   const bool IsArray = T->isArrayType();
8752   const bool IsFunction = T->isFunctionType();
8753 
8754   // Address of function is used to silence the function warning.
8755   if (IsAddressOf && IsFunction) {
8756     return;
8757   }
8758 
8759   // Found nothing.
8760   if (!IsAddressOf && !IsFunction && !IsArray)
8761     return;
8762 
8763   // Pretty print the expression for the diagnostic.
8764   std::string Str;
8765   llvm::raw_string_ostream S(Str);
8766   E->printPretty(S, nullptr, getPrintingPolicy());
8767 
8768   unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare
8769                               : diag::warn_impcast_pointer_to_bool;
8770   enum {
8771     AddressOf,
8772     FunctionPointer,
8773     ArrayPointer
8774   } DiagType;
8775   if (IsAddressOf)
8776     DiagType = AddressOf;
8777   else if (IsFunction)
8778     DiagType = FunctionPointer;
8779   else if (IsArray)
8780     DiagType = ArrayPointer;
8781   else
8782     llvm_unreachable("Could not determine diagnostic.");
8783   Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange()
8784                                 << Range << IsEqual;
8785 
8786   if (!IsFunction)
8787     return;
8788 
8789   // Suggest '&' to silence the function warning.
8790   Diag(E->getExprLoc(), diag::note_function_warning_silence)
8791       << FixItHint::CreateInsertion(E->getLocStart(), "&");
8792 
8793   // Check to see if '()' fixit should be emitted.
8794   QualType ReturnType;
8795   UnresolvedSet<4> NonTemplateOverloads;
8796   tryExprAsCall(*E, ReturnType, NonTemplateOverloads);
8797   if (ReturnType.isNull())
8798     return;
8799 
8800   if (IsCompare) {
8801     // There are two cases here.  If there is null constant, the only suggest
8802     // for a pointer return type.  If the null is 0, then suggest if the return
8803     // type is a pointer or an integer type.
8804     if (!ReturnType->isPointerType()) {
8805       if (NullKind == Expr::NPCK_ZeroExpression ||
8806           NullKind == Expr::NPCK_ZeroLiteral) {
8807         if (!ReturnType->isIntegerType())
8808           return;
8809       } else {
8810         return;
8811       }
8812     }
8813   } else { // !IsCompare
8814     // For function to bool, only suggest if the function pointer has bool
8815     // return type.
8816     if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
8817       return;
8818   }
8819   Diag(E->getExprLoc(), diag::note_function_to_function_call)
8820       << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()");
8821 }
8822 
8823 /// Diagnoses "dangerous" implicit conversions within the given
8824 /// expression (which is a full expression).  Implements -Wconversion
8825 /// and -Wsign-compare.
8826 ///
8827 /// \param CC the "context" location of the implicit conversion, i.e.
8828 ///   the most location of the syntactic entity requiring the implicit
8829 ///   conversion
CheckImplicitConversions(Expr * E,SourceLocation CC)8830 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
8831   // Don't diagnose in unevaluated contexts.
8832   if (isUnevaluatedContext())
8833     return;
8834 
8835   // Don't diagnose for value- or type-dependent expressions.
8836   if (E->isTypeDependent() || E->isValueDependent())
8837     return;
8838 
8839   // Check for array bounds violations in cases where the check isn't triggered
8840   // elsewhere for other Expr types (like BinaryOperators), e.g. when an
8841   // ArraySubscriptExpr is on the RHS of a variable initialization.
8842   CheckArrayAccess(E);
8843 
8844   // This is not the right CC for (e.g.) a variable initialization.
8845   AnalyzeImplicitConversions(*this, E, CC);
8846 }
8847 
8848 /// CheckBoolLikeConversion - Check conversion of given expression to boolean.
8849 /// Input argument E is a logical expression.
CheckBoolLikeConversion(Expr * E,SourceLocation CC)8850 void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) {
8851   ::CheckBoolLikeConversion(*this, E, CC);
8852 }
8853 
8854 /// Diagnose when expression is an integer constant expression and its evaluation
8855 /// results in integer overflow
CheckForIntOverflow(Expr * E)8856 void Sema::CheckForIntOverflow (Expr *E) {
8857   // Use a work list to deal with nested struct initializers.
8858   SmallVector<Expr *, 2> Exprs(1, E);
8859 
8860   do {
8861     Expr *E = Exprs.pop_back_val();
8862 
8863     if (isa<BinaryOperator>(E->IgnoreParenCasts())) {
8864       E->IgnoreParenCasts()->EvaluateForOverflow(Context);
8865       continue;
8866     }
8867 
8868     if (auto InitList = dyn_cast<InitListExpr>(E))
8869       Exprs.append(InitList->inits().begin(), InitList->inits().end());
8870   } while (!Exprs.empty());
8871 }
8872 
8873 namespace {
8874 /// \brief Visitor for expressions which looks for unsequenced operations on the
8875 /// same object.
8876 class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> {
8877   typedef EvaluatedExprVisitor<SequenceChecker> Base;
8878 
8879   /// \brief A tree of sequenced regions within an expression. Two regions are
8880   /// unsequenced if one is an ancestor or a descendent of the other. When we
8881   /// finish processing an expression with sequencing, such as a comma
8882   /// expression, we fold its tree nodes into its parent, since they are
8883   /// unsequenced with respect to nodes we will visit later.
8884   class SequenceTree {
8885     struct Value {
Value__anon6c85a6980c11::SequenceChecker::SequenceTree::Value8886       explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {}
8887       unsigned Parent : 31;
8888       unsigned Merged : 1;
8889     };
8890     SmallVector<Value, 8> Values;
8891 
8892   public:
8893     /// \brief A region within an expression which may be sequenced with respect
8894     /// to some other region.
8895     class Seq {
Seq(unsigned N)8896       explicit Seq(unsigned N) : Index(N) {}
8897       unsigned Index;
8898       friend class SequenceTree;
8899     public:
Seq()8900       Seq() : Index(0) {}
8901     };
8902 
SequenceTree()8903     SequenceTree() { Values.push_back(Value(0)); }
root() const8904     Seq root() const { return Seq(0); }
8905 
8906     /// \brief Create a new sequence of operations, which is an unsequenced
8907     /// subset of \p Parent. This sequence of operations is sequenced with
8908     /// respect to other children of \p Parent.
allocate(Seq Parent)8909     Seq allocate(Seq Parent) {
8910       Values.push_back(Value(Parent.Index));
8911       return Seq(Values.size() - 1);
8912     }
8913 
8914     /// \brief Merge a sequence of operations into its parent.
merge(Seq S)8915     void merge(Seq S) {
8916       Values[S.Index].Merged = true;
8917     }
8918 
8919     /// \brief Determine whether two operations are unsequenced. This operation
8920     /// is asymmetric: \p Cur should be the more recent sequence, and \p Old
8921     /// should have been merged into its parent as appropriate.
isUnsequenced(Seq Cur,Seq Old)8922     bool isUnsequenced(Seq Cur, Seq Old) {
8923       unsigned C = representative(Cur.Index);
8924       unsigned Target = representative(Old.Index);
8925       while (C >= Target) {
8926         if (C == Target)
8927           return true;
8928         C = Values[C].Parent;
8929       }
8930       return false;
8931     }
8932 
8933   private:
8934     /// \brief Pick a representative for a sequence.
representative(unsigned K)8935     unsigned representative(unsigned K) {
8936       if (Values[K].Merged)
8937         // Perform path compression as we go.
8938         return Values[K].Parent = representative(Values[K].Parent);
8939       return K;
8940     }
8941   };
8942 
8943   /// An object for which we can track unsequenced uses.
8944   typedef NamedDecl *Object;
8945 
8946   /// Different flavors of object usage which we track. We only track the
8947   /// least-sequenced usage of each kind.
8948   enum UsageKind {
8949     /// A read of an object. Multiple unsequenced reads are OK.
8950     UK_Use,
8951     /// A modification of an object which is sequenced before the value
8952     /// computation of the expression, such as ++n in C++.
8953     UK_ModAsValue,
8954     /// A modification of an object which is not sequenced before the value
8955     /// computation of the expression, such as n++.
8956     UK_ModAsSideEffect,
8957 
8958     UK_Count = UK_ModAsSideEffect + 1
8959   };
8960 
8961   struct Usage {
Usage__anon6c85a6980c11::SequenceChecker::Usage8962     Usage() : Use(nullptr), Seq() {}
8963     Expr *Use;
8964     SequenceTree::Seq Seq;
8965   };
8966 
8967   struct UsageInfo {
UsageInfo__anon6c85a6980c11::SequenceChecker::UsageInfo8968     UsageInfo() : Diagnosed(false) {}
8969     Usage Uses[UK_Count];
8970     /// Have we issued a diagnostic for this variable already?
8971     bool Diagnosed;
8972   };
8973   typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap;
8974 
8975   Sema &SemaRef;
8976   /// Sequenced regions within the expression.
8977   SequenceTree Tree;
8978   /// Declaration modifications and references which we have seen.
8979   UsageInfoMap UsageMap;
8980   /// The region we are currently within.
8981   SequenceTree::Seq Region;
8982   /// Filled in with declarations which were modified as a side-effect
8983   /// (that is, post-increment operations).
8984   SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect;
8985   /// Expressions to check later. We defer checking these to reduce
8986   /// stack usage.
8987   SmallVectorImpl<Expr *> &WorkList;
8988 
8989   /// RAII object wrapping the visitation of a sequenced subexpression of an
8990   /// expression. At the end of this process, the side-effects of the evaluation
8991   /// become sequenced with respect to the value computation of the result, so
8992   /// we downgrade any UK_ModAsSideEffect within the evaluation to
8993   /// UK_ModAsValue.
8994   struct SequencedSubexpression {
SequencedSubexpression__anon6c85a6980c11::SequenceChecker::SequencedSubexpression8995     SequencedSubexpression(SequenceChecker &Self)
8996       : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) {
8997       Self.ModAsSideEffect = &ModAsSideEffect;
8998     }
~SequencedSubexpression__anon6c85a6980c11::SequenceChecker::SequencedSubexpression8999     ~SequencedSubexpression() {
9000       for (auto &M : llvm::reverse(ModAsSideEffect)) {
9001         UsageInfo &U = Self.UsageMap[M.first];
9002         auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect];
9003         Self.addUsage(U, M.first, SideEffectUsage.Use, UK_ModAsValue);
9004         SideEffectUsage = M.second;
9005       }
9006       Self.ModAsSideEffect = OldModAsSideEffect;
9007     }
9008 
9009     SequenceChecker &Self;
9010     SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect;
9011     SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect;
9012   };
9013 
9014   /// RAII object wrapping the visitation of a subexpression which we might
9015   /// choose to evaluate as a constant. If any subexpression is evaluated and
9016   /// found to be non-constant, this allows us to suppress the evaluation of
9017   /// the outer expression.
9018   class EvaluationTracker {
9019   public:
EvaluationTracker(SequenceChecker & Self)9020     EvaluationTracker(SequenceChecker &Self)
9021         : Self(Self), Prev(Self.EvalTracker), EvalOK(true) {
9022       Self.EvalTracker = this;
9023     }
~EvaluationTracker()9024     ~EvaluationTracker() {
9025       Self.EvalTracker = Prev;
9026       if (Prev)
9027         Prev->EvalOK &= EvalOK;
9028     }
9029 
evaluate(const Expr * E,bool & Result)9030     bool evaluate(const Expr *E, bool &Result) {
9031       if (!EvalOK || E->isValueDependent())
9032         return false;
9033       EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context);
9034       return EvalOK;
9035     }
9036 
9037   private:
9038     SequenceChecker &Self;
9039     EvaluationTracker *Prev;
9040     bool EvalOK;
9041   } *EvalTracker;
9042 
9043   /// \brief Find the object which is produced by the specified expression,
9044   /// if any.
getObject(Expr * E,bool Mod) const9045   Object getObject(Expr *E, bool Mod) const {
9046     E = E->IgnoreParenCasts();
9047     if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
9048       if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec))
9049         return getObject(UO->getSubExpr(), Mod);
9050     } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
9051       if (BO->getOpcode() == BO_Comma)
9052         return getObject(BO->getRHS(), Mod);
9053       if (Mod && BO->isAssignmentOp())
9054         return getObject(BO->getLHS(), Mod);
9055     } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
9056       // FIXME: Check for more interesting cases, like "x.n = ++x.n".
9057       if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts()))
9058         return ME->getMemberDecl();
9059     } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
9060       // FIXME: If this is a reference, map through to its value.
9061       return DRE->getDecl();
9062     return nullptr;
9063   }
9064 
9065   /// \brief Note that an object was modified or used by an expression.
addUsage(UsageInfo & UI,Object O,Expr * Ref,UsageKind UK)9066   void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) {
9067     Usage &U = UI.Uses[UK];
9068     if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) {
9069       if (UK == UK_ModAsSideEffect && ModAsSideEffect)
9070         ModAsSideEffect->push_back(std::make_pair(O, U));
9071       U.Use = Ref;
9072       U.Seq = Region;
9073     }
9074   }
9075   /// \brief Check whether a modification or use conflicts with a prior usage.
checkUsage(Object O,UsageInfo & UI,Expr * Ref,UsageKind OtherKind,bool IsModMod)9076   void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind,
9077                   bool IsModMod) {
9078     if (UI.Diagnosed)
9079       return;
9080 
9081     const Usage &U = UI.Uses[OtherKind];
9082     if (!U.Use || !Tree.isUnsequenced(Region, U.Seq))
9083       return;
9084 
9085     Expr *Mod = U.Use;
9086     Expr *ModOrUse = Ref;
9087     if (OtherKind == UK_Use)
9088       std::swap(Mod, ModOrUse);
9089 
9090     SemaRef.Diag(Mod->getExprLoc(),
9091                  IsModMod ? diag::warn_unsequenced_mod_mod
9092                           : diag::warn_unsequenced_mod_use)
9093       << O << SourceRange(ModOrUse->getExprLoc());
9094     UI.Diagnosed = true;
9095   }
9096 
notePreUse(Object O,Expr * Use)9097   void notePreUse(Object O, Expr *Use) {
9098     UsageInfo &U = UsageMap[O];
9099     // Uses conflict with other modifications.
9100     checkUsage(O, U, Use, UK_ModAsValue, false);
9101   }
notePostUse(Object O,Expr * Use)9102   void notePostUse(Object O, Expr *Use) {
9103     UsageInfo &U = UsageMap[O];
9104     checkUsage(O, U, Use, UK_ModAsSideEffect, false);
9105     addUsage(U, O, Use, UK_Use);
9106   }
9107 
notePreMod(Object O,Expr * Mod)9108   void notePreMod(Object O, Expr *Mod) {
9109     UsageInfo &U = UsageMap[O];
9110     // Modifications conflict with other modifications and with uses.
9111     checkUsage(O, U, Mod, UK_ModAsValue, true);
9112     checkUsage(O, U, Mod, UK_Use, false);
9113   }
notePostMod(Object O,Expr * Use,UsageKind UK)9114   void notePostMod(Object O, Expr *Use, UsageKind UK) {
9115     UsageInfo &U = UsageMap[O];
9116     checkUsage(O, U, Use, UK_ModAsSideEffect, true);
9117     addUsage(U, O, Use, UK);
9118   }
9119 
9120 public:
SequenceChecker(Sema & S,Expr * E,SmallVectorImpl<Expr * > & WorkList)9121   SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList)
9122       : Base(S.Context), SemaRef(S), Region(Tree.root()),
9123         ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) {
9124     Visit(E);
9125   }
9126 
VisitStmt(Stmt * S)9127   void VisitStmt(Stmt *S) {
9128     // Skip all statements which aren't expressions for now.
9129   }
9130 
VisitExpr(Expr * E)9131   void VisitExpr(Expr *E) {
9132     // By default, just recurse to evaluated subexpressions.
9133     Base::VisitStmt(E);
9134   }
9135 
VisitCastExpr(CastExpr * E)9136   void VisitCastExpr(CastExpr *E) {
9137     Object O = Object();
9138     if (E->getCastKind() == CK_LValueToRValue)
9139       O = getObject(E->getSubExpr(), false);
9140 
9141     if (O)
9142       notePreUse(O, E);
9143     VisitExpr(E);
9144     if (O)
9145       notePostUse(O, E);
9146   }
9147 
VisitBinComma(BinaryOperator * BO)9148   void VisitBinComma(BinaryOperator *BO) {
9149     // C++11 [expr.comma]p1:
9150     //   Every value computation and side effect associated with the left
9151     //   expression is sequenced before every value computation and side
9152     //   effect associated with the right expression.
9153     SequenceTree::Seq LHS = Tree.allocate(Region);
9154     SequenceTree::Seq RHS = Tree.allocate(Region);
9155     SequenceTree::Seq OldRegion = Region;
9156 
9157     {
9158       SequencedSubexpression SeqLHS(*this);
9159       Region = LHS;
9160       Visit(BO->getLHS());
9161     }
9162 
9163     Region = RHS;
9164     Visit(BO->getRHS());
9165 
9166     Region = OldRegion;
9167 
9168     // Forget that LHS and RHS are sequenced. They are both unsequenced
9169     // with respect to other stuff.
9170     Tree.merge(LHS);
9171     Tree.merge(RHS);
9172   }
9173 
VisitBinAssign(BinaryOperator * BO)9174   void VisitBinAssign(BinaryOperator *BO) {
9175     // The modification is sequenced after the value computation of the LHS
9176     // and RHS, so check it before inspecting the operands and update the
9177     // map afterwards.
9178     Object O = getObject(BO->getLHS(), true);
9179     if (!O)
9180       return VisitExpr(BO);
9181 
9182     notePreMod(O, BO);
9183 
9184     // C++11 [expr.ass]p7:
9185     //   E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated
9186     //   only once.
9187     //
9188     // Therefore, for a compound assignment operator, O is considered used
9189     // everywhere except within the evaluation of E1 itself.
9190     if (isa<CompoundAssignOperator>(BO))
9191       notePreUse(O, BO);
9192 
9193     Visit(BO->getLHS());
9194 
9195     if (isa<CompoundAssignOperator>(BO))
9196       notePostUse(O, BO);
9197 
9198     Visit(BO->getRHS());
9199 
9200     // C++11 [expr.ass]p1:
9201     //   the assignment is sequenced [...] before the value computation of the
9202     //   assignment expression.
9203     // C11 6.5.16/3 has no such rule.
9204     notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
9205                                                        : UK_ModAsSideEffect);
9206   }
9207 
VisitCompoundAssignOperator(CompoundAssignOperator * CAO)9208   void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) {
9209     VisitBinAssign(CAO);
9210   }
9211 
VisitUnaryPreInc(UnaryOperator * UO)9212   void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
VisitUnaryPreDec(UnaryOperator * UO)9213   void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
VisitUnaryPreIncDec(UnaryOperator * UO)9214   void VisitUnaryPreIncDec(UnaryOperator *UO) {
9215     Object O = getObject(UO->getSubExpr(), true);
9216     if (!O)
9217       return VisitExpr(UO);
9218 
9219     notePreMod(O, UO);
9220     Visit(UO->getSubExpr());
9221     // C++11 [expr.pre.incr]p1:
9222     //   the expression ++x is equivalent to x+=1
9223     notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
9224                                                        : UK_ModAsSideEffect);
9225   }
9226 
VisitUnaryPostInc(UnaryOperator * UO)9227   void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
VisitUnaryPostDec(UnaryOperator * UO)9228   void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
VisitUnaryPostIncDec(UnaryOperator * UO)9229   void VisitUnaryPostIncDec(UnaryOperator *UO) {
9230     Object O = getObject(UO->getSubExpr(), true);
9231     if (!O)
9232       return VisitExpr(UO);
9233 
9234     notePreMod(O, UO);
9235     Visit(UO->getSubExpr());
9236     notePostMod(O, UO, UK_ModAsSideEffect);
9237   }
9238 
9239   /// Don't visit the RHS of '&&' or '||' if it might not be evaluated.
VisitBinLOr(BinaryOperator * BO)9240   void VisitBinLOr(BinaryOperator *BO) {
9241     // The side-effects of the LHS of an '&&' are sequenced before the
9242     // value computation of the RHS, and hence before the value computation
9243     // of the '&&' itself, unless the LHS evaluates to zero. We treat them
9244     // as if they were unconditionally sequenced.
9245     EvaluationTracker Eval(*this);
9246     {
9247       SequencedSubexpression Sequenced(*this);
9248       Visit(BO->getLHS());
9249     }
9250 
9251     bool Result;
9252     if (Eval.evaluate(BO->getLHS(), Result)) {
9253       if (!Result)
9254         Visit(BO->getRHS());
9255     } else {
9256       // Check for unsequenced operations in the RHS, treating it as an
9257       // entirely separate evaluation.
9258       //
9259       // FIXME: If there are operations in the RHS which are unsequenced
9260       // with respect to operations outside the RHS, and those operations
9261       // are unconditionally evaluated, diagnose them.
9262       WorkList.push_back(BO->getRHS());
9263     }
9264   }
VisitBinLAnd(BinaryOperator * BO)9265   void VisitBinLAnd(BinaryOperator *BO) {
9266     EvaluationTracker Eval(*this);
9267     {
9268       SequencedSubexpression Sequenced(*this);
9269       Visit(BO->getLHS());
9270     }
9271 
9272     bool Result;
9273     if (Eval.evaluate(BO->getLHS(), Result)) {
9274       if (Result)
9275         Visit(BO->getRHS());
9276     } else {
9277       WorkList.push_back(BO->getRHS());
9278     }
9279   }
9280 
9281   // Only visit the condition, unless we can be sure which subexpression will
9282   // be chosen.
VisitAbstractConditionalOperator(AbstractConditionalOperator * CO)9283   void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) {
9284     EvaluationTracker Eval(*this);
9285     {
9286       SequencedSubexpression Sequenced(*this);
9287       Visit(CO->getCond());
9288     }
9289 
9290     bool Result;
9291     if (Eval.evaluate(CO->getCond(), Result))
9292       Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr());
9293     else {
9294       WorkList.push_back(CO->getTrueExpr());
9295       WorkList.push_back(CO->getFalseExpr());
9296     }
9297   }
9298 
VisitCallExpr(CallExpr * CE)9299   void VisitCallExpr(CallExpr *CE) {
9300     // C++11 [intro.execution]p15:
9301     //   When calling a function [...], every value computation and side effect
9302     //   associated with any argument expression, or with the postfix expression
9303     //   designating the called function, is sequenced before execution of every
9304     //   expression or statement in the body of the function [and thus before
9305     //   the value computation of its result].
9306     SequencedSubexpression Sequenced(*this);
9307     Base::VisitCallExpr(CE);
9308 
9309     // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions.
9310   }
9311 
VisitCXXConstructExpr(CXXConstructExpr * CCE)9312   void VisitCXXConstructExpr(CXXConstructExpr *CCE) {
9313     // This is a call, so all subexpressions are sequenced before the result.
9314     SequencedSubexpression Sequenced(*this);
9315 
9316     if (!CCE->isListInitialization())
9317       return VisitExpr(CCE);
9318 
9319     // In C++11, list initializations are sequenced.
9320     SmallVector<SequenceTree::Seq, 32> Elts;
9321     SequenceTree::Seq Parent = Region;
9322     for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(),
9323                                         E = CCE->arg_end();
9324          I != E; ++I) {
9325       Region = Tree.allocate(Parent);
9326       Elts.push_back(Region);
9327       Visit(*I);
9328     }
9329 
9330     // Forget that the initializers are sequenced.
9331     Region = Parent;
9332     for (unsigned I = 0; I < Elts.size(); ++I)
9333       Tree.merge(Elts[I]);
9334   }
9335 
VisitInitListExpr(InitListExpr * ILE)9336   void VisitInitListExpr(InitListExpr *ILE) {
9337     if (!SemaRef.getLangOpts().CPlusPlus11)
9338       return VisitExpr(ILE);
9339 
9340     // In C++11, list initializations are sequenced.
9341     SmallVector<SequenceTree::Seq, 32> Elts;
9342     SequenceTree::Seq Parent = Region;
9343     for (unsigned I = 0; I < ILE->getNumInits(); ++I) {
9344       Expr *E = ILE->getInit(I);
9345       if (!E) continue;
9346       Region = Tree.allocate(Parent);
9347       Elts.push_back(Region);
9348       Visit(E);
9349     }
9350 
9351     // Forget that the initializers are sequenced.
9352     Region = Parent;
9353     for (unsigned I = 0; I < Elts.size(); ++I)
9354       Tree.merge(Elts[I]);
9355   }
9356 };
9357 } // end anonymous namespace
9358 
CheckUnsequencedOperations(Expr * E)9359 void Sema::CheckUnsequencedOperations(Expr *E) {
9360   SmallVector<Expr *, 8> WorkList;
9361   WorkList.push_back(E);
9362   while (!WorkList.empty()) {
9363     Expr *Item = WorkList.pop_back_val();
9364     SequenceChecker(*this, Item, WorkList);
9365   }
9366 }
9367 
CheckCompletedExpr(Expr * E,SourceLocation CheckLoc,bool IsConstexpr)9368 void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc,
9369                               bool IsConstexpr) {
9370   CheckImplicitConversions(E, CheckLoc);
9371   CheckUnsequencedOperations(E);
9372   if (!IsConstexpr && !E->isValueDependent())
9373     CheckForIntOverflow(E);
9374 }
9375 
CheckBitFieldInitialization(SourceLocation InitLoc,FieldDecl * BitField,Expr * Init)9376 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
9377                                        FieldDecl *BitField,
9378                                        Expr *Init) {
9379   (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
9380 }
9381 
diagnoseArrayStarInParamType(Sema & S,QualType PType,SourceLocation Loc)9382 static void diagnoseArrayStarInParamType(Sema &S, QualType PType,
9383                                          SourceLocation Loc) {
9384   if (!PType->isVariablyModifiedType())
9385     return;
9386   if (const auto *PointerTy = dyn_cast<PointerType>(PType)) {
9387     diagnoseArrayStarInParamType(S, PointerTy->getPointeeType(), Loc);
9388     return;
9389   }
9390   if (const auto *ReferenceTy = dyn_cast<ReferenceType>(PType)) {
9391     diagnoseArrayStarInParamType(S, ReferenceTy->getPointeeType(), Loc);
9392     return;
9393   }
9394   if (const auto *ParenTy = dyn_cast<ParenType>(PType)) {
9395     diagnoseArrayStarInParamType(S, ParenTy->getInnerType(), Loc);
9396     return;
9397   }
9398 
9399   const ArrayType *AT = S.Context.getAsArrayType(PType);
9400   if (!AT)
9401     return;
9402 
9403   if (AT->getSizeModifier() != ArrayType::Star) {
9404     diagnoseArrayStarInParamType(S, AT->getElementType(), Loc);
9405     return;
9406   }
9407 
9408   S.Diag(Loc, diag::err_array_star_in_function_definition);
9409 }
9410 
9411 /// CheckParmsForFunctionDef - Check that the parameters of the given
9412 /// function are appropriate for the definition of a function. This
9413 /// takes care of any checks that cannot be performed on the
9414 /// declaration itself, e.g., that the types of each of the function
9415 /// parameters are complete.
CheckParmsForFunctionDef(ArrayRef<ParmVarDecl * > Parameters,bool CheckParameterNames)9416 bool Sema::CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
9417                                     bool CheckParameterNames) {
9418   bool HasInvalidParm = false;
9419   for (ParmVarDecl *Param : Parameters) {
9420     // C99 6.7.5.3p4: the parameters in a parameter type list in a
9421     // function declarator that is part of a function definition of
9422     // that function shall not have incomplete type.
9423     //
9424     // This is also C++ [dcl.fct]p6.
9425     if (!Param->isInvalidDecl() &&
9426         RequireCompleteType(Param->getLocation(), Param->getType(),
9427                             diag::err_typecheck_decl_incomplete_type)) {
9428       Param->setInvalidDecl();
9429       HasInvalidParm = true;
9430     }
9431 
9432     // C99 6.9.1p5: If the declarator includes a parameter type list, the
9433     // declaration of each parameter shall include an identifier.
9434     if (CheckParameterNames &&
9435         Param->getIdentifier() == nullptr &&
9436         !Param->isImplicit() &&
9437         !getLangOpts().CPlusPlus)
9438       Diag(Param->getLocation(), diag::err_parameter_name_omitted);
9439 
9440     // C99 6.7.5.3p12:
9441     //   If the function declarator is not part of a definition of that
9442     //   function, parameters may have incomplete type and may use the [*]
9443     //   notation in their sequences of declarator specifiers to specify
9444     //   variable length array types.
9445     QualType PType = Param->getOriginalType();
9446     // FIXME: This diagnostic should point the '[*]' if source-location
9447     // information is added for it.
9448     diagnoseArrayStarInParamType(*this, PType, Param->getLocation());
9449 
9450     // MSVC destroys objects passed by value in the callee.  Therefore a
9451     // function definition which takes such a parameter must be able to call the
9452     // object's destructor.  However, we don't perform any direct access check
9453     // on the dtor.
9454     if (getLangOpts().CPlusPlus && Context.getTargetInfo()
9455                                        .getCXXABI()
9456                                        .areArgsDestroyedLeftToRightInCallee()) {
9457       if (!Param->isInvalidDecl()) {
9458         if (const RecordType *RT = Param->getType()->getAs<RecordType>()) {
9459           CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
9460           if (!ClassDecl->isInvalidDecl() &&
9461               !ClassDecl->hasIrrelevantDestructor() &&
9462               !ClassDecl->isDependentContext()) {
9463             CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl);
9464             MarkFunctionReferenced(Param->getLocation(), Destructor);
9465             DiagnoseUseOfDecl(Destructor, Param->getLocation());
9466           }
9467         }
9468       }
9469     }
9470 
9471     // Parameters with the pass_object_size attribute only need to be marked
9472     // constant at function definitions. Because we lack information about
9473     // whether we're on a declaration or definition when we're instantiating the
9474     // attribute, we need to check for constness here.
9475     if (const auto *Attr = Param->getAttr<PassObjectSizeAttr>())
9476       if (!Param->getType().isConstQualified())
9477         Diag(Param->getLocation(), diag::err_attribute_pointers_only)
9478             << Attr->getSpelling() << 1;
9479   }
9480 
9481   return HasInvalidParm;
9482 }
9483 
9484 /// CheckCastAlign - Implements -Wcast-align, which warns when a
9485 /// pointer cast increases the alignment requirements.
CheckCastAlign(Expr * Op,QualType T,SourceRange TRange)9486 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
9487   // This is actually a lot of work to potentially be doing on every
9488   // cast; don't do it if we're ignoring -Wcast_align (as is the default).
9489   if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin()))
9490     return;
9491 
9492   // Ignore dependent types.
9493   if (T->isDependentType() || Op->getType()->isDependentType())
9494     return;
9495 
9496   // Require that the destination be a pointer type.
9497   const PointerType *DestPtr = T->getAs<PointerType>();
9498   if (!DestPtr) return;
9499 
9500   // If the destination has alignment 1, we're done.
9501   QualType DestPointee = DestPtr->getPointeeType();
9502   if (DestPointee->isIncompleteType()) return;
9503   CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
9504   if (DestAlign.isOne()) return;
9505 
9506   // Require that the source be a pointer type.
9507   const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
9508   if (!SrcPtr) return;
9509   QualType SrcPointee = SrcPtr->getPointeeType();
9510 
9511   // Whitelist casts from cv void*.  We already implicitly
9512   // whitelisted casts to cv void*, since they have alignment 1.
9513   // Also whitelist casts involving incomplete types, which implicitly
9514   // includes 'void'.
9515   if (SrcPointee->isIncompleteType()) return;
9516 
9517   CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
9518   if (SrcAlign >= DestAlign) return;
9519 
9520   Diag(TRange.getBegin(), diag::warn_cast_align)
9521     << Op->getType() << T
9522     << static_cast<unsigned>(SrcAlign.getQuantity())
9523     << static_cast<unsigned>(DestAlign.getQuantity())
9524     << TRange << Op->getSourceRange();
9525 }
9526 
9527 /// \brief Check whether this array fits the idiom of a size-one tail padded
9528 /// array member of a struct.
9529 ///
9530 /// We avoid emitting out-of-bounds access warnings for such arrays as they are
9531 /// commonly used to emulate flexible arrays in C89 code.
IsTailPaddedMemberArray(Sema & S,const llvm::APInt & Size,const NamedDecl * ND)9532 static bool IsTailPaddedMemberArray(Sema &S, const llvm::APInt &Size,
9533                                     const NamedDecl *ND) {
9534   if (Size != 1 || !ND) return false;
9535 
9536   const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
9537   if (!FD) return false;
9538 
9539   // Don't consider sizes resulting from macro expansions or template argument
9540   // substitution to form C89 tail-padded arrays.
9541 
9542   TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
9543   while (TInfo) {
9544     TypeLoc TL = TInfo->getTypeLoc();
9545     // Look through typedefs.
9546     if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) {
9547       const TypedefNameDecl *TDL = TTL.getTypedefNameDecl();
9548       TInfo = TDL->getTypeSourceInfo();
9549       continue;
9550     }
9551     if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) {
9552       const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
9553       if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
9554         return false;
9555     }
9556     break;
9557   }
9558 
9559   const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
9560   if (!RD) return false;
9561   if (RD->isUnion()) return false;
9562   if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
9563     if (!CRD->isStandardLayout()) return false;
9564   }
9565 
9566   // See if this is the last field decl in the record.
9567   const Decl *D = FD;
9568   while ((D = D->getNextDeclInContext()))
9569     if (isa<FieldDecl>(D))
9570       return false;
9571   return true;
9572 }
9573 
CheckArrayAccess(const Expr * BaseExpr,const Expr * IndexExpr,const ArraySubscriptExpr * ASE,bool AllowOnePastEnd,bool IndexNegated)9574 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
9575                             const ArraySubscriptExpr *ASE,
9576                             bool AllowOnePastEnd, bool IndexNegated) {
9577   IndexExpr = IndexExpr->IgnoreParenImpCasts();
9578   if (IndexExpr->isValueDependent())
9579     return;
9580 
9581   const Type *EffectiveType =
9582       BaseExpr->getType()->getPointeeOrArrayElementType();
9583   BaseExpr = BaseExpr->IgnoreParenCasts();
9584   const ConstantArrayType *ArrayTy =
9585     Context.getAsConstantArrayType(BaseExpr->getType());
9586   if (!ArrayTy)
9587     return;
9588 
9589   llvm::APSInt index;
9590   if (!IndexExpr->EvaluateAsInt(index, Context, Expr::SE_AllowSideEffects))
9591     return;
9592   if (IndexNegated)
9593     index = -index;
9594 
9595   const NamedDecl *ND = nullptr;
9596   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
9597     ND = dyn_cast<NamedDecl>(DRE->getDecl());
9598   if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
9599     ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
9600 
9601   if (index.isUnsigned() || !index.isNegative()) {
9602     llvm::APInt size = ArrayTy->getSize();
9603     if (!size.isStrictlyPositive())
9604       return;
9605 
9606     const Type *BaseType = BaseExpr->getType()->getPointeeOrArrayElementType();
9607     if (BaseType != EffectiveType) {
9608       // Make sure we're comparing apples to apples when comparing index to size
9609       uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
9610       uint64_t array_typesize = Context.getTypeSize(BaseType);
9611       // Handle ptrarith_typesize being zero, such as when casting to void*
9612       if (!ptrarith_typesize) ptrarith_typesize = 1;
9613       if (ptrarith_typesize != array_typesize) {
9614         // There's a cast to a different size type involved
9615         uint64_t ratio = array_typesize / ptrarith_typesize;
9616         // TODO: Be smarter about handling cases where array_typesize is not a
9617         // multiple of ptrarith_typesize
9618         if (ptrarith_typesize * ratio == array_typesize)
9619           size *= llvm::APInt(size.getBitWidth(), ratio);
9620       }
9621     }
9622 
9623     if (size.getBitWidth() > index.getBitWidth())
9624       index = index.zext(size.getBitWidth());
9625     else if (size.getBitWidth() < index.getBitWidth())
9626       size = size.zext(index.getBitWidth());
9627 
9628     // For array subscripting the index must be less than size, but for pointer
9629     // arithmetic also allow the index (offset) to be equal to size since
9630     // computing the next address after the end of the array is legal and
9631     // commonly done e.g. in C++ iterators and range-based for loops.
9632     if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
9633       return;
9634 
9635     // Also don't warn for arrays of size 1 which are members of some
9636     // structure. These are often used to approximate flexible arrays in C89
9637     // code.
9638     if (IsTailPaddedMemberArray(*this, size, ND))
9639       return;
9640 
9641     // Suppress the warning if the subscript expression (as identified by the
9642     // ']' location) and the index expression are both from macro expansions
9643     // within a system header.
9644     if (ASE) {
9645       SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
9646           ASE->getRBracketLoc());
9647       if (SourceMgr.isInSystemHeader(RBracketLoc)) {
9648         SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
9649             IndexExpr->getLocStart());
9650         if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc))
9651           return;
9652       }
9653     }
9654 
9655     unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
9656     if (ASE)
9657       DiagID = diag::warn_array_index_exceeds_bounds;
9658 
9659     DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
9660                         PDiag(DiagID) << index.toString(10, true)
9661                           << size.toString(10, true)
9662                           << (unsigned)size.getLimitedValue(~0U)
9663                           << IndexExpr->getSourceRange());
9664   } else {
9665     unsigned DiagID = diag::warn_array_index_precedes_bounds;
9666     if (!ASE) {
9667       DiagID = diag::warn_ptr_arith_precedes_bounds;
9668       if (index.isNegative()) index = -index;
9669     }
9670 
9671     DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
9672                         PDiag(DiagID) << index.toString(10, true)
9673                           << IndexExpr->getSourceRange());
9674   }
9675 
9676   if (!ND) {
9677     // Try harder to find a NamedDecl to point at in the note.
9678     while (const ArraySubscriptExpr *ASE =
9679            dyn_cast<ArraySubscriptExpr>(BaseExpr))
9680       BaseExpr = ASE->getBase()->IgnoreParenCasts();
9681     if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
9682       ND = dyn_cast<NamedDecl>(DRE->getDecl());
9683     if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
9684       ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
9685   }
9686 
9687   if (ND)
9688     DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
9689                         PDiag(diag::note_array_index_out_of_bounds)
9690                           << ND->getDeclName());
9691 }
9692 
CheckArrayAccess(const Expr * expr)9693 void Sema::CheckArrayAccess(const Expr *expr) {
9694   int AllowOnePastEnd = 0;
9695   while (expr) {
9696     expr = expr->IgnoreParenImpCasts();
9697     switch (expr->getStmtClass()) {
9698       case Stmt::ArraySubscriptExprClass: {
9699         const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
9700         CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
9701                          AllowOnePastEnd > 0);
9702         return;
9703       }
9704       case Stmt::OMPArraySectionExprClass: {
9705         const OMPArraySectionExpr *ASE = cast<OMPArraySectionExpr>(expr);
9706         if (ASE->getLowerBound())
9707           CheckArrayAccess(ASE->getBase(), ASE->getLowerBound(),
9708                            /*ASE=*/nullptr, AllowOnePastEnd > 0);
9709         return;
9710       }
9711       case Stmt::UnaryOperatorClass: {
9712         // Only unwrap the * and & unary operators
9713         const UnaryOperator *UO = cast<UnaryOperator>(expr);
9714         expr = UO->getSubExpr();
9715         switch (UO->getOpcode()) {
9716           case UO_AddrOf:
9717             AllowOnePastEnd++;
9718             break;
9719           case UO_Deref:
9720             AllowOnePastEnd--;
9721             break;
9722           default:
9723             return;
9724         }
9725         break;
9726       }
9727       case Stmt::ConditionalOperatorClass: {
9728         const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
9729         if (const Expr *lhs = cond->getLHS())
9730           CheckArrayAccess(lhs);
9731         if (const Expr *rhs = cond->getRHS())
9732           CheckArrayAccess(rhs);
9733         return;
9734       }
9735       default:
9736         return;
9737     }
9738   }
9739 }
9740 
9741 //===--- CHECK: Objective-C retain cycles ----------------------------------//
9742 
9743 namespace {
9744   struct RetainCycleOwner {
RetainCycleOwner__anon6c85a6980d11::RetainCycleOwner9745     RetainCycleOwner() : Variable(nullptr), Indirect(false) {}
9746     VarDecl *Variable;
9747     SourceRange Range;
9748     SourceLocation Loc;
9749     bool Indirect;
9750 
setLocsFrom__anon6c85a6980d11::RetainCycleOwner9751     void setLocsFrom(Expr *e) {
9752       Loc = e->getExprLoc();
9753       Range = e->getSourceRange();
9754     }
9755   };
9756 } // end anonymous namespace
9757 
9758 /// Consider whether capturing the given variable can possibly lead to
9759 /// a retain cycle.
considerVariable(VarDecl * var,Expr * ref,RetainCycleOwner & owner)9760 static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
9761   // In ARC, it's captured strongly iff the variable has __strong
9762   // lifetime.  In MRR, it's captured strongly if the variable is
9763   // __block and has an appropriate type.
9764   if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
9765     return false;
9766 
9767   owner.Variable = var;
9768   if (ref)
9769     owner.setLocsFrom(ref);
9770   return true;
9771 }
9772 
findRetainCycleOwner(Sema & S,Expr * e,RetainCycleOwner & owner)9773 static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
9774   while (true) {
9775     e = e->IgnoreParens();
9776     if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
9777       switch (cast->getCastKind()) {
9778       case CK_BitCast:
9779       case CK_LValueBitCast:
9780       case CK_LValueToRValue:
9781       case CK_ARCReclaimReturnedObject:
9782         e = cast->getSubExpr();
9783         continue;
9784 
9785       default:
9786         return false;
9787       }
9788     }
9789 
9790     if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
9791       ObjCIvarDecl *ivar = ref->getDecl();
9792       if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
9793         return false;
9794 
9795       // Try to find a retain cycle in the base.
9796       if (!findRetainCycleOwner(S, ref->getBase(), owner))
9797         return false;
9798 
9799       if (ref->isFreeIvar()) owner.setLocsFrom(ref);
9800       owner.Indirect = true;
9801       return true;
9802     }
9803 
9804     if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
9805       VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
9806       if (!var) return false;
9807       return considerVariable(var, ref, owner);
9808     }
9809 
9810     if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
9811       if (member->isArrow()) return false;
9812 
9813       // Don't count this as an indirect ownership.
9814       e = member->getBase();
9815       continue;
9816     }
9817 
9818     if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
9819       // Only pay attention to pseudo-objects on property references.
9820       ObjCPropertyRefExpr *pre
9821         = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
9822                                               ->IgnoreParens());
9823       if (!pre) return false;
9824       if (pre->isImplicitProperty()) return false;
9825       ObjCPropertyDecl *property = pre->getExplicitProperty();
9826       if (!property->isRetaining() &&
9827           !(property->getPropertyIvarDecl() &&
9828             property->getPropertyIvarDecl()->getType()
9829               .getObjCLifetime() == Qualifiers::OCL_Strong))
9830           return false;
9831 
9832       owner.Indirect = true;
9833       if (pre->isSuperReceiver()) {
9834         owner.Variable = S.getCurMethodDecl()->getSelfDecl();
9835         if (!owner.Variable)
9836           return false;
9837         owner.Loc = pre->getLocation();
9838         owner.Range = pre->getSourceRange();
9839         return true;
9840       }
9841       e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
9842                               ->getSourceExpr());
9843       continue;
9844     }
9845 
9846     // Array ivars?
9847 
9848     return false;
9849   }
9850 }
9851 
9852 namespace {
9853   struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
FindCaptureVisitor__anon6c85a6980e11::FindCaptureVisitor9854     FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
9855       : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
9856         Context(Context), Variable(variable), Capturer(nullptr),
9857         VarWillBeReased(false) {}
9858     ASTContext &Context;
9859     VarDecl *Variable;
9860     Expr *Capturer;
9861     bool VarWillBeReased;
9862 
VisitDeclRefExpr__anon6c85a6980e11::FindCaptureVisitor9863     void VisitDeclRefExpr(DeclRefExpr *ref) {
9864       if (ref->getDecl() == Variable && !Capturer)
9865         Capturer = ref;
9866     }
9867 
VisitObjCIvarRefExpr__anon6c85a6980e11::FindCaptureVisitor9868     void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
9869       if (Capturer) return;
9870       Visit(ref->getBase());
9871       if (Capturer && ref->isFreeIvar())
9872         Capturer = ref;
9873     }
9874 
VisitBlockExpr__anon6c85a6980e11::FindCaptureVisitor9875     void VisitBlockExpr(BlockExpr *block) {
9876       // Look inside nested blocks
9877       if (block->getBlockDecl()->capturesVariable(Variable))
9878         Visit(block->getBlockDecl()->getBody());
9879     }
9880 
VisitOpaqueValueExpr__anon6c85a6980e11::FindCaptureVisitor9881     void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
9882       if (Capturer) return;
9883       if (OVE->getSourceExpr())
9884         Visit(OVE->getSourceExpr());
9885     }
VisitBinaryOperator__anon6c85a6980e11::FindCaptureVisitor9886     void VisitBinaryOperator(BinaryOperator *BinOp) {
9887       if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign)
9888         return;
9889       Expr *LHS = BinOp->getLHS();
9890       if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) {
9891         if (DRE->getDecl() != Variable)
9892           return;
9893         if (Expr *RHS = BinOp->getRHS()) {
9894           RHS = RHS->IgnoreParenCasts();
9895           llvm::APSInt Value;
9896           VarWillBeReased =
9897             (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0);
9898         }
9899       }
9900     }
9901   };
9902 } // end anonymous namespace
9903 
9904 /// Check whether the given argument is a block which captures a
9905 /// variable.
findCapturingExpr(Sema & S,Expr * e,RetainCycleOwner & owner)9906 static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
9907   assert(owner.Variable && owner.Loc.isValid());
9908 
9909   e = e->IgnoreParenCasts();
9910 
9911   // Look through [^{...} copy] and Block_copy(^{...}).
9912   if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
9913     Selector Cmd = ME->getSelector();
9914     if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
9915       e = ME->getInstanceReceiver();
9916       if (!e)
9917         return nullptr;
9918       e = e->IgnoreParenCasts();
9919     }
9920   } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
9921     if (CE->getNumArgs() == 1) {
9922       FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
9923       if (Fn) {
9924         const IdentifierInfo *FnI = Fn->getIdentifier();
9925         if (FnI && FnI->isStr("_Block_copy")) {
9926           e = CE->getArg(0)->IgnoreParenCasts();
9927         }
9928       }
9929     }
9930   }
9931 
9932   BlockExpr *block = dyn_cast<BlockExpr>(e);
9933   if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
9934     return nullptr;
9935 
9936   FindCaptureVisitor visitor(S.Context, owner.Variable);
9937   visitor.Visit(block->getBlockDecl()->getBody());
9938   return visitor.VarWillBeReased ? nullptr : visitor.Capturer;
9939 }
9940 
diagnoseRetainCycle(Sema & S,Expr * capturer,RetainCycleOwner & owner)9941 static void diagnoseRetainCycle(Sema &S, Expr *capturer,
9942                                 RetainCycleOwner &owner) {
9943   assert(capturer);
9944   assert(owner.Variable && owner.Loc.isValid());
9945 
9946   S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
9947     << owner.Variable << capturer->getSourceRange();
9948   S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
9949     << owner.Indirect << owner.Range;
9950 }
9951 
9952 /// Check for a keyword selector that starts with the word 'add' or
9953 /// 'set'.
isSetterLikeSelector(Selector sel)9954 static bool isSetterLikeSelector(Selector sel) {
9955   if (sel.isUnarySelector()) return false;
9956 
9957   StringRef str = sel.getNameForSlot(0);
9958   while (!str.empty() && str.front() == '_') str = str.substr(1);
9959   if (str.startswith("set"))
9960     str = str.substr(3);
9961   else if (str.startswith("add")) {
9962     // Specially whitelist 'addOperationWithBlock:'.
9963     if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
9964       return false;
9965     str = str.substr(3);
9966   }
9967   else
9968     return false;
9969 
9970   if (str.empty()) return true;
9971   return !isLowercase(str.front());
9972 }
9973 
GetNSMutableArrayArgumentIndex(Sema & S,ObjCMessageExpr * Message)9974 static Optional<int> GetNSMutableArrayArgumentIndex(Sema &S,
9975                                                     ObjCMessageExpr *Message) {
9976   bool IsMutableArray = S.NSAPIObj->isSubclassOfNSClass(
9977                                                 Message->getReceiverInterface(),
9978                                                 NSAPI::ClassId_NSMutableArray);
9979   if (!IsMutableArray) {
9980     return None;
9981   }
9982 
9983   Selector Sel = Message->getSelector();
9984 
9985   Optional<NSAPI::NSArrayMethodKind> MKOpt =
9986     S.NSAPIObj->getNSArrayMethodKind(Sel);
9987   if (!MKOpt) {
9988     return None;
9989   }
9990 
9991   NSAPI::NSArrayMethodKind MK = *MKOpt;
9992 
9993   switch (MK) {
9994     case NSAPI::NSMutableArr_addObject:
9995     case NSAPI::NSMutableArr_insertObjectAtIndex:
9996     case NSAPI::NSMutableArr_setObjectAtIndexedSubscript:
9997       return 0;
9998     case NSAPI::NSMutableArr_replaceObjectAtIndex:
9999       return 1;
10000 
10001     default:
10002       return None;
10003   }
10004 
10005   return None;
10006 }
10007 
10008 static
GetNSMutableDictionaryArgumentIndex(Sema & S,ObjCMessageExpr * Message)10009 Optional<int> GetNSMutableDictionaryArgumentIndex(Sema &S,
10010                                                   ObjCMessageExpr *Message) {
10011   bool IsMutableDictionary = S.NSAPIObj->isSubclassOfNSClass(
10012                                             Message->getReceiverInterface(),
10013                                             NSAPI::ClassId_NSMutableDictionary);
10014   if (!IsMutableDictionary) {
10015     return None;
10016   }
10017 
10018   Selector Sel = Message->getSelector();
10019 
10020   Optional<NSAPI::NSDictionaryMethodKind> MKOpt =
10021     S.NSAPIObj->getNSDictionaryMethodKind(Sel);
10022   if (!MKOpt) {
10023     return None;
10024   }
10025 
10026   NSAPI::NSDictionaryMethodKind MK = *MKOpt;
10027 
10028   switch (MK) {
10029     case NSAPI::NSMutableDict_setObjectForKey:
10030     case NSAPI::NSMutableDict_setValueForKey:
10031     case NSAPI::NSMutableDict_setObjectForKeyedSubscript:
10032       return 0;
10033 
10034     default:
10035       return None;
10036   }
10037 
10038   return None;
10039 }
10040 
GetNSSetArgumentIndex(Sema & S,ObjCMessageExpr * Message)10041 static Optional<int> GetNSSetArgumentIndex(Sema &S, ObjCMessageExpr *Message) {
10042   bool IsMutableSet = S.NSAPIObj->isSubclassOfNSClass(
10043                                                 Message->getReceiverInterface(),
10044                                                 NSAPI::ClassId_NSMutableSet);
10045 
10046   bool IsMutableOrderedSet = S.NSAPIObj->isSubclassOfNSClass(
10047                                             Message->getReceiverInterface(),
10048                                             NSAPI::ClassId_NSMutableOrderedSet);
10049   if (!IsMutableSet && !IsMutableOrderedSet) {
10050     return None;
10051   }
10052 
10053   Selector Sel = Message->getSelector();
10054 
10055   Optional<NSAPI::NSSetMethodKind> MKOpt = S.NSAPIObj->getNSSetMethodKind(Sel);
10056   if (!MKOpt) {
10057     return None;
10058   }
10059 
10060   NSAPI::NSSetMethodKind MK = *MKOpt;
10061 
10062   switch (MK) {
10063     case NSAPI::NSMutableSet_addObject:
10064     case NSAPI::NSOrderedSet_setObjectAtIndex:
10065     case NSAPI::NSOrderedSet_setObjectAtIndexedSubscript:
10066     case NSAPI::NSOrderedSet_insertObjectAtIndex:
10067       return 0;
10068     case NSAPI::NSOrderedSet_replaceObjectAtIndexWithObject:
10069       return 1;
10070   }
10071 
10072   return None;
10073 }
10074 
CheckObjCCircularContainer(ObjCMessageExpr * Message)10075 void Sema::CheckObjCCircularContainer(ObjCMessageExpr *Message) {
10076   if (!Message->isInstanceMessage()) {
10077     return;
10078   }
10079 
10080   Optional<int> ArgOpt;
10081 
10082   if (!(ArgOpt = GetNSMutableArrayArgumentIndex(*this, Message)) &&
10083       !(ArgOpt = GetNSMutableDictionaryArgumentIndex(*this, Message)) &&
10084       !(ArgOpt = GetNSSetArgumentIndex(*this, Message))) {
10085     return;
10086   }
10087 
10088   int ArgIndex = *ArgOpt;
10089 
10090   Expr *Arg = Message->getArg(ArgIndex)->IgnoreImpCasts();
10091   if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Arg)) {
10092     Arg = OE->getSourceExpr()->IgnoreImpCasts();
10093   }
10094 
10095   if (Message->getReceiverKind() == ObjCMessageExpr::SuperInstance) {
10096     if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) {
10097       if (ArgRE->isObjCSelfExpr()) {
10098         Diag(Message->getSourceRange().getBegin(),
10099              diag::warn_objc_circular_container)
10100           << ArgRE->getDecl()->getName() << StringRef("super");
10101       }
10102     }
10103   } else {
10104     Expr *Receiver = Message->getInstanceReceiver()->IgnoreImpCasts();
10105 
10106     if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Receiver)) {
10107       Receiver = OE->getSourceExpr()->IgnoreImpCasts();
10108     }
10109 
10110     if (DeclRefExpr *ReceiverRE = dyn_cast<DeclRefExpr>(Receiver)) {
10111       if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) {
10112         if (ReceiverRE->getDecl() == ArgRE->getDecl()) {
10113           ValueDecl *Decl = ReceiverRE->getDecl();
10114           Diag(Message->getSourceRange().getBegin(),
10115                diag::warn_objc_circular_container)
10116             << Decl->getName() << Decl->getName();
10117           if (!ArgRE->isObjCSelfExpr()) {
10118             Diag(Decl->getLocation(),
10119                  diag::note_objc_circular_container_declared_here)
10120               << Decl->getName();
10121           }
10122         }
10123       }
10124     } else if (ObjCIvarRefExpr *IvarRE = dyn_cast<ObjCIvarRefExpr>(Receiver)) {
10125       if (ObjCIvarRefExpr *IvarArgRE = dyn_cast<ObjCIvarRefExpr>(Arg)) {
10126         if (IvarRE->getDecl() == IvarArgRE->getDecl()) {
10127           ObjCIvarDecl *Decl = IvarRE->getDecl();
10128           Diag(Message->getSourceRange().getBegin(),
10129                diag::warn_objc_circular_container)
10130             << Decl->getName() << Decl->getName();
10131           Diag(Decl->getLocation(),
10132                diag::note_objc_circular_container_declared_here)
10133             << Decl->getName();
10134         }
10135       }
10136     }
10137   }
10138 }
10139 
10140 /// Check a message send to see if it's likely to cause a retain cycle.
checkRetainCycles(ObjCMessageExpr * msg)10141 void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
10142   // Only check instance methods whose selector looks like a setter.
10143   if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
10144     return;
10145 
10146   // Try to find a variable that the receiver is strongly owned by.
10147   RetainCycleOwner owner;
10148   if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
10149     if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
10150       return;
10151   } else {
10152     assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
10153     owner.Variable = getCurMethodDecl()->getSelfDecl();
10154     owner.Loc = msg->getSuperLoc();
10155     owner.Range = msg->getSuperLoc();
10156   }
10157 
10158   // Check whether the receiver is captured by any of the arguments.
10159   for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
10160     if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
10161       return diagnoseRetainCycle(*this, capturer, owner);
10162 }
10163 
10164 /// Check a property assign to see if it's likely to cause a retain cycle.
checkRetainCycles(Expr * receiver,Expr * argument)10165 void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
10166   RetainCycleOwner owner;
10167   if (!findRetainCycleOwner(*this, receiver, owner))
10168     return;
10169 
10170   if (Expr *capturer = findCapturingExpr(*this, argument, owner))
10171     diagnoseRetainCycle(*this, capturer, owner);
10172 }
10173 
checkRetainCycles(VarDecl * Var,Expr * Init)10174 void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
10175   RetainCycleOwner Owner;
10176   if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner))
10177     return;
10178 
10179   // Because we don't have an expression for the variable, we have to set the
10180   // location explicitly here.
10181   Owner.Loc = Var->getLocation();
10182   Owner.Range = Var->getSourceRange();
10183 
10184   if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
10185     diagnoseRetainCycle(*this, Capturer, Owner);
10186 }
10187 
checkUnsafeAssignLiteral(Sema & S,SourceLocation Loc,Expr * RHS,bool isProperty)10188 static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc,
10189                                      Expr *RHS, bool isProperty) {
10190   // Check if RHS is an Objective-C object literal, which also can get
10191   // immediately zapped in a weak reference.  Note that we explicitly
10192   // allow ObjCStringLiterals, since those are designed to never really die.
10193   RHS = RHS->IgnoreParenImpCasts();
10194 
10195   // This enum needs to match with the 'select' in
10196   // warn_objc_arc_literal_assign (off-by-1).
10197   Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS);
10198   if (Kind == Sema::LK_String || Kind == Sema::LK_None)
10199     return false;
10200 
10201   S.Diag(Loc, diag::warn_arc_literal_assign)
10202     << (unsigned) Kind
10203     << (isProperty ? 0 : 1)
10204     << RHS->getSourceRange();
10205 
10206   return true;
10207 }
10208 
checkUnsafeAssignObject(Sema & S,SourceLocation Loc,Qualifiers::ObjCLifetime LT,Expr * RHS,bool isProperty)10209 static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc,
10210                                     Qualifiers::ObjCLifetime LT,
10211                                     Expr *RHS, bool isProperty) {
10212   // Strip off any implicit cast added to get to the one ARC-specific.
10213   while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
10214     if (cast->getCastKind() == CK_ARCConsumeObject) {
10215       S.Diag(Loc, diag::warn_arc_retained_assign)
10216         << (LT == Qualifiers::OCL_ExplicitNone)
10217         << (isProperty ? 0 : 1)
10218         << RHS->getSourceRange();
10219       return true;
10220     }
10221     RHS = cast->getSubExpr();
10222   }
10223 
10224   if (LT == Qualifiers::OCL_Weak &&
10225       checkUnsafeAssignLiteral(S, Loc, RHS, isProperty))
10226     return true;
10227 
10228   return false;
10229 }
10230 
checkUnsafeAssigns(SourceLocation Loc,QualType LHS,Expr * RHS)10231 bool Sema::checkUnsafeAssigns(SourceLocation Loc,
10232                               QualType LHS, Expr *RHS) {
10233   Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
10234 
10235   if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
10236     return false;
10237 
10238   if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false))
10239     return true;
10240 
10241   return false;
10242 }
10243 
checkUnsafeExprAssigns(SourceLocation Loc,Expr * LHS,Expr * RHS)10244 void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
10245                               Expr *LHS, Expr *RHS) {
10246   QualType LHSType;
10247   // PropertyRef on LHS type need be directly obtained from
10248   // its declaration as it has a PseudoType.
10249   ObjCPropertyRefExpr *PRE
10250     = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
10251   if (PRE && !PRE->isImplicitProperty()) {
10252     const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
10253     if (PD)
10254       LHSType = PD->getType();
10255   }
10256 
10257   if (LHSType.isNull())
10258     LHSType = LHS->getType();
10259 
10260   Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
10261 
10262   if (LT == Qualifiers::OCL_Weak) {
10263     if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc))
10264       getCurFunction()->markSafeWeakUse(LHS);
10265   }
10266 
10267   if (checkUnsafeAssigns(Loc, LHSType, RHS))
10268     return;
10269 
10270   // FIXME. Check for other life times.
10271   if (LT != Qualifiers::OCL_None)
10272     return;
10273 
10274   if (PRE) {
10275     if (PRE->isImplicitProperty())
10276       return;
10277     const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
10278     if (!PD)
10279       return;
10280 
10281     unsigned Attributes = PD->getPropertyAttributes();
10282     if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
10283       // when 'assign' attribute was not explicitly specified
10284       // by user, ignore it and rely on property type itself
10285       // for lifetime info.
10286       unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
10287       if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
10288           LHSType->isObjCRetainableType())
10289         return;
10290 
10291       while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
10292         if (cast->getCastKind() == CK_ARCConsumeObject) {
10293           Diag(Loc, diag::warn_arc_retained_property_assign)
10294           << RHS->getSourceRange();
10295           return;
10296         }
10297         RHS = cast->getSubExpr();
10298       }
10299     }
10300     else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
10301       if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true))
10302         return;
10303     }
10304   }
10305 }
10306 
10307 //===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
10308 
10309 namespace {
ShouldDiagnoseEmptyStmtBody(const SourceManager & SourceMgr,SourceLocation StmtLoc,const NullStmt * Body)10310 bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
10311                                  SourceLocation StmtLoc,
10312                                  const NullStmt *Body) {
10313   // Do not warn if the body is a macro that expands to nothing, e.g:
10314   //
10315   // #define CALL(x)
10316   // if (condition)
10317   //   CALL(0);
10318   //
10319   if (Body->hasLeadingEmptyMacro())
10320     return false;
10321 
10322   // Get line numbers of statement and body.
10323   bool StmtLineInvalid;
10324   unsigned StmtLine = SourceMgr.getPresumedLineNumber(StmtLoc,
10325                                                       &StmtLineInvalid);
10326   if (StmtLineInvalid)
10327     return false;
10328 
10329   bool BodyLineInvalid;
10330   unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
10331                                                       &BodyLineInvalid);
10332   if (BodyLineInvalid)
10333     return false;
10334 
10335   // Warn if null statement and body are on the same line.
10336   if (StmtLine != BodyLine)
10337     return false;
10338 
10339   return true;
10340 }
10341 } // end anonymous namespace
10342 
DiagnoseEmptyStmtBody(SourceLocation StmtLoc,const Stmt * Body,unsigned DiagID)10343 void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
10344                                  const Stmt *Body,
10345                                  unsigned DiagID) {
10346   // Since this is a syntactic check, don't emit diagnostic for template
10347   // instantiations, this just adds noise.
10348   if (CurrentInstantiationScope)
10349     return;
10350 
10351   // The body should be a null statement.
10352   const NullStmt *NBody = dyn_cast<NullStmt>(Body);
10353   if (!NBody)
10354     return;
10355 
10356   // Do the usual checks.
10357   if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
10358     return;
10359 
10360   Diag(NBody->getSemiLoc(), DiagID);
10361   Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
10362 }
10363 
DiagnoseEmptyLoopBody(const Stmt * S,const Stmt * PossibleBody)10364 void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
10365                                  const Stmt *PossibleBody) {
10366   assert(!CurrentInstantiationScope); // Ensured by caller
10367 
10368   SourceLocation StmtLoc;
10369   const Stmt *Body;
10370   unsigned DiagID;
10371   if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
10372     StmtLoc = FS->getRParenLoc();
10373     Body = FS->getBody();
10374     DiagID = diag::warn_empty_for_body;
10375   } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
10376     StmtLoc = WS->getCond()->getSourceRange().getEnd();
10377     Body = WS->getBody();
10378     DiagID = diag::warn_empty_while_body;
10379   } else
10380     return; // Neither `for' nor `while'.
10381 
10382   // The body should be a null statement.
10383   const NullStmt *NBody = dyn_cast<NullStmt>(Body);
10384   if (!NBody)
10385     return;
10386 
10387   // Skip expensive checks if diagnostic is disabled.
10388   if (Diags.isIgnored(DiagID, NBody->getSemiLoc()))
10389     return;
10390 
10391   // Do the usual checks.
10392   if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
10393     return;
10394 
10395   // `for(...);' and `while(...);' are popular idioms, so in order to keep
10396   // noise level low, emit diagnostics only if for/while is followed by a
10397   // CompoundStmt, e.g.:
10398   //    for (int i = 0; i < n; i++);
10399   //    {
10400   //      a(i);
10401   //    }
10402   // or if for/while is followed by a statement with more indentation
10403   // than for/while itself:
10404   //    for (int i = 0; i < n; i++);
10405   //      a(i);
10406   bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
10407   if (!ProbableTypo) {
10408     bool BodyColInvalid;
10409     unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
10410                              PossibleBody->getLocStart(),
10411                              &BodyColInvalid);
10412     if (BodyColInvalid)
10413       return;
10414 
10415     bool StmtColInvalid;
10416     unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
10417                              S->getLocStart(),
10418                              &StmtColInvalid);
10419     if (StmtColInvalid)
10420       return;
10421 
10422     if (BodyCol > StmtCol)
10423       ProbableTypo = true;
10424   }
10425 
10426   if (ProbableTypo) {
10427     Diag(NBody->getSemiLoc(), DiagID);
10428     Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
10429   }
10430 }
10431 
10432 //===--- CHECK: Warn on self move with std::move. -------------------------===//
10433 
10434 /// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
DiagnoseSelfMove(const Expr * LHSExpr,const Expr * RHSExpr,SourceLocation OpLoc)10435 void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
10436                              SourceLocation OpLoc) {
10437   if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc))
10438     return;
10439 
10440   if (!ActiveTemplateInstantiations.empty())
10441     return;
10442 
10443   // Strip parens and casts away.
10444   LHSExpr = LHSExpr->IgnoreParenImpCasts();
10445   RHSExpr = RHSExpr->IgnoreParenImpCasts();
10446 
10447   // Check for a call expression
10448   const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr);
10449   if (!CE || CE->getNumArgs() != 1)
10450     return;
10451 
10452   // Check for a call to std::move
10453   const FunctionDecl *FD = CE->getDirectCallee();
10454   if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() ||
10455       !FD->getIdentifier()->isStr("move"))
10456     return;
10457 
10458   // Get argument from std::move
10459   RHSExpr = CE->getArg(0);
10460 
10461   const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
10462   const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
10463 
10464   // Two DeclRefExpr's, check that the decls are the same.
10465   if (LHSDeclRef && RHSDeclRef) {
10466     if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
10467       return;
10468     if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
10469         RHSDeclRef->getDecl()->getCanonicalDecl())
10470       return;
10471 
10472     Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
10473                                         << LHSExpr->getSourceRange()
10474                                         << RHSExpr->getSourceRange();
10475     return;
10476   }
10477 
10478   // Member variables require a different approach to check for self moves.
10479   // MemberExpr's are the same if every nested MemberExpr refers to the same
10480   // Decl and that the base Expr's are DeclRefExpr's with the same Decl or
10481   // the base Expr's are CXXThisExpr's.
10482   const Expr *LHSBase = LHSExpr;
10483   const Expr *RHSBase = RHSExpr;
10484   const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr);
10485   const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr);
10486   if (!LHSME || !RHSME)
10487     return;
10488 
10489   while (LHSME && RHSME) {
10490     if (LHSME->getMemberDecl()->getCanonicalDecl() !=
10491         RHSME->getMemberDecl()->getCanonicalDecl())
10492       return;
10493 
10494     LHSBase = LHSME->getBase();
10495     RHSBase = RHSME->getBase();
10496     LHSME = dyn_cast<MemberExpr>(LHSBase);
10497     RHSME = dyn_cast<MemberExpr>(RHSBase);
10498   }
10499 
10500   LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase);
10501   RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase);
10502   if (LHSDeclRef && RHSDeclRef) {
10503     if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
10504       return;
10505     if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
10506         RHSDeclRef->getDecl()->getCanonicalDecl())
10507       return;
10508 
10509     Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
10510                                         << LHSExpr->getSourceRange()
10511                                         << RHSExpr->getSourceRange();
10512     return;
10513   }
10514 
10515   if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase))
10516     Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
10517                                         << LHSExpr->getSourceRange()
10518                                         << RHSExpr->getSourceRange();
10519 }
10520 
10521 //===--- Layout compatibility ----------------------------------------------//
10522 
10523 namespace {
10524 
10525 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
10526 
10527 /// \brief Check if two enumeration types are layout-compatible.
isLayoutCompatible(ASTContext & C,EnumDecl * ED1,EnumDecl * ED2)10528 bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
10529   // C++11 [dcl.enum] p8:
10530   // Two enumeration types are layout-compatible if they have the same
10531   // underlying type.
10532   return ED1->isComplete() && ED2->isComplete() &&
10533          C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
10534 }
10535 
10536 /// \brief Check if two fields are layout-compatible.
isLayoutCompatible(ASTContext & C,FieldDecl * Field1,FieldDecl * Field2)10537 bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
10538   if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
10539     return false;
10540 
10541   if (Field1->isBitField() != Field2->isBitField())
10542     return false;
10543 
10544   if (Field1->isBitField()) {
10545     // Make sure that the bit-fields are the same length.
10546     unsigned Bits1 = Field1->getBitWidthValue(C);
10547     unsigned Bits2 = Field2->getBitWidthValue(C);
10548 
10549     if (Bits1 != Bits2)
10550       return false;
10551   }
10552 
10553   return true;
10554 }
10555 
10556 /// \brief Check if two standard-layout structs are layout-compatible.
10557 /// (C++11 [class.mem] p17)
isLayoutCompatibleStruct(ASTContext & C,RecordDecl * RD1,RecordDecl * RD2)10558 bool isLayoutCompatibleStruct(ASTContext &C,
10559                               RecordDecl *RD1,
10560                               RecordDecl *RD2) {
10561   // If both records are C++ classes, check that base classes match.
10562   if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
10563     // If one of records is a CXXRecordDecl we are in C++ mode,
10564     // thus the other one is a CXXRecordDecl, too.
10565     const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
10566     // Check number of base classes.
10567     if (D1CXX->getNumBases() != D2CXX->getNumBases())
10568       return false;
10569 
10570     // Check the base classes.
10571     for (CXXRecordDecl::base_class_const_iterator
10572                Base1 = D1CXX->bases_begin(),
10573            BaseEnd1 = D1CXX->bases_end(),
10574               Base2 = D2CXX->bases_begin();
10575          Base1 != BaseEnd1;
10576          ++Base1, ++Base2) {
10577       if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
10578         return false;
10579     }
10580   } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
10581     // If only RD2 is a C++ class, it should have zero base classes.
10582     if (D2CXX->getNumBases() > 0)
10583       return false;
10584   }
10585 
10586   // Check the fields.
10587   RecordDecl::field_iterator Field2 = RD2->field_begin(),
10588                              Field2End = RD2->field_end(),
10589                              Field1 = RD1->field_begin(),
10590                              Field1End = RD1->field_end();
10591   for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
10592     if (!isLayoutCompatible(C, *Field1, *Field2))
10593       return false;
10594   }
10595   if (Field1 != Field1End || Field2 != Field2End)
10596     return false;
10597 
10598   return true;
10599 }
10600 
10601 /// \brief Check if two standard-layout unions are layout-compatible.
10602 /// (C++11 [class.mem] p18)
isLayoutCompatibleUnion(ASTContext & C,RecordDecl * RD1,RecordDecl * RD2)10603 bool isLayoutCompatibleUnion(ASTContext &C,
10604                              RecordDecl *RD1,
10605                              RecordDecl *RD2) {
10606   llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
10607   for (auto *Field2 : RD2->fields())
10608     UnmatchedFields.insert(Field2);
10609 
10610   for (auto *Field1 : RD1->fields()) {
10611     llvm::SmallPtrSet<FieldDecl *, 8>::iterator
10612         I = UnmatchedFields.begin(),
10613         E = UnmatchedFields.end();
10614 
10615     for ( ; I != E; ++I) {
10616       if (isLayoutCompatible(C, Field1, *I)) {
10617         bool Result = UnmatchedFields.erase(*I);
10618         (void) Result;
10619         assert(Result);
10620         break;
10621       }
10622     }
10623     if (I == E)
10624       return false;
10625   }
10626 
10627   return UnmatchedFields.empty();
10628 }
10629 
isLayoutCompatible(ASTContext & C,RecordDecl * RD1,RecordDecl * RD2)10630 bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
10631   if (RD1->isUnion() != RD2->isUnion())
10632     return false;
10633 
10634   if (RD1->isUnion())
10635     return isLayoutCompatibleUnion(C, RD1, RD2);
10636   else
10637     return isLayoutCompatibleStruct(C, RD1, RD2);
10638 }
10639 
10640 /// \brief Check if two types are layout-compatible in C++11 sense.
isLayoutCompatible(ASTContext & C,QualType T1,QualType T2)10641 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
10642   if (T1.isNull() || T2.isNull())
10643     return false;
10644 
10645   // C++11 [basic.types] p11:
10646   // If two types T1 and T2 are the same type, then T1 and T2 are
10647   // layout-compatible types.
10648   if (C.hasSameType(T1, T2))
10649     return true;
10650 
10651   T1 = T1.getCanonicalType().getUnqualifiedType();
10652   T2 = T2.getCanonicalType().getUnqualifiedType();
10653 
10654   const Type::TypeClass TC1 = T1->getTypeClass();
10655   const Type::TypeClass TC2 = T2->getTypeClass();
10656 
10657   if (TC1 != TC2)
10658     return false;
10659 
10660   if (TC1 == Type::Enum) {
10661     return isLayoutCompatible(C,
10662                               cast<EnumType>(T1)->getDecl(),
10663                               cast<EnumType>(T2)->getDecl());
10664   } else if (TC1 == Type::Record) {
10665     if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
10666       return false;
10667 
10668     return isLayoutCompatible(C,
10669                               cast<RecordType>(T1)->getDecl(),
10670                               cast<RecordType>(T2)->getDecl());
10671   }
10672 
10673   return false;
10674 }
10675 } // end anonymous namespace
10676 
10677 //===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
10678 
10679 namespace {
10680 /// \brief Given a type tag expression find the type tag itself.
10681 ///
10682 /// \param TypeExpr Type tag expression, as it appears in user's code.
10683 ///
10684 /// \param VD Declaration of an identifier that appears in a type tag.
10685 ///
10686 /// \param MagicValue Type tag magic value.
FindTypeTagExpr(const Expr * TypeExpr,const ASTContext & Ctx,const ValueDecl ** VD,uint64_t * MagicValue)10687 bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
10688                      const ValueDecl **VD, uint64_t *MagicValue) {
10689   while(true) {
10690     if (!TypeExpr)
10691       return false;
10692 
10693     TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
10694 
10695     switch (TypeExpr->getStmtClass()) {
10696     case Stmt::UnaryOperatorClass: {
10697       const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
10698       if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
10699         TypeExpr = UO->getSubExpr();
10700         continue;
10701       }
10702       return false;
10703     }
10704 
10705     case Stmt::DeclRefExprClass: {
10706       const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
10707       *VD = DRE->getDecl();
10708       return true;
10709     }
10710 
10711     case Stmt::IntegerLiteralClass: {
10712       const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
10713       llvm::APInt MagicValueAPInt = IL->getValue();
10714       if (MagicValueAPInt.getActiveBits() <= 64) {
10715         *MagicValue = MagicValueAPInt.getZExtValue();
10716         return true;
10717       } else
10718         return false;
10719     }
10720 
10721     case Stmt::BinaryConditionalOperatorClass:
10722     case Stmt::ConditionalOperatorClass: {
10723       const AbstractConditionalOperator *ACO =
10724           cast<AbstractConditionalOperator>(TypeExpr);
10725       bool Result;
10726       if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
10727         if (Result)
10728           TypeExpr = ACO->getTrueExpr();
10729         else
10730           TypeExpr = ACO->getFalseExpr();
10731         continue;
10732       }
10733       return false;
10734     }
10735 
10736     case Stmt::BinaryOperatorClass: {
10737       const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
10738       if (BO->getOpcode() == BO_Comma) {
10739         TypeExpr = BO->getRHS();
10740         continue;
10741       }
10742       return false;
10743     }
10744 
10745     default:
10746       return false;
10747     }
10748   }
10749 }
10750 
10751 /// \brief Retrieve the C type corresponding to type tag TypeExpr.
10752 ///
10753 /// \param TypeExpr Expression that specifies a type tag.
10754 ///
10755 /// \param MagicValues Registered magic values.
10756 ///
10757 /// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
10758 ///        kind.
10759 ///
10760 /// \param TypeInfo Information about the corresponding C type.
10761 ///
10762 /// \returns true if the corresponding C type was found.
GetMatchingCType(const IdentifierInfo * ArgumentKind,const Expr * TypeExpr,const ASTContext & Ctx,const llvm::DenseMap<Sema::TypeTagMagicValue,Sema::TypeTagData> * MagicValues,bool & FoundWrongKind,Sema::TypeTagData & TypeInfo)10763 bool GetMatchingCType(
10764         const IdentifierInfo *ArgumentKind,
10765         const Expr *TypeExpr, const ASTContext &Ctx,
10766         const llvm::DenseMap<Sema::TypeTagMagicValue,
10767                              Sema::TypeTagData> *MagicValues,
10768         bool &FoundWrongKind,
10769         Sema::TypeTagData &TypeInfo) {
10770   FoundWrongKind = false;
10771 
10772   // Variable declaration that has type_tag_for_datatype attribute.
10773   const ValueDecl *VD = nullptr;
10774 
10775   uint64_t MagicValue;
10776 
10777   if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
10778     return false;
10779 
10780   if (VD) {
10781     if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) {
10782       if (I->getArgumentKind() != ArgumentKind) {
10783         FoundWrongKind = true;
10784         return false;
10785       }
10786       TypeInfo.Type = I->getMatchingCType();
10787       TypeInfo.LayoutCompatible = I->getLayoutCompatible();
10788       TypeInfo.MustBeNull = I->getMustBeNull();
10789       return true;
10790     }
10791     return false;
10792   }
10793 
10794   if (!MagicValues)
10795     return false;
10796 
10797   llvm::DenseMap<Sema::TypeTagMagicValue,
10798                  Sema::TypeTagData>::const_iterator I =
10799       MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
10800   if (I == MagicValues->end())
10801     return false;
10802 
10803   TypeInfo = I->second;
10804   return true;
10805 }
10806 } // end anonymous namespace
10807 
RegisterTypeTagForDatatype(const IdentifierInfo * ArgumentKind,uint64_t MagicValue,QualType Type,bool LayoutCompatible,bool MustBeNull)10808 void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
10809                                       uint64_t MagicValue, QualType Type,
10810                                       bool LayoutCompatible,
10811                                       bool MustBeNull) {
10812   if (!TypeTagForDatatypeMagicValues)
10813     TypeTagForDatatypeMagicValues.reset(
10814         new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
10815 
10816   TypeTagMagicValue Magic(ArgumentKind, MagicValue);
10817   (*TypeTagForDatatypeMagicValues)[Magic] =
10818       TypeTagData(Type, LayoutCompatible, MustBeNull);
10819 }
10820 
10821 namespace {
IsSameCharType(QualType T1,QualType T2)10822 bool IsSameCharType(QualType T1, QualType T2) {
10823   const BuiltinType *BT1 = T1->getAs<BuiltinType>();
10824   if (!BT1)
10825     return false;
10826 
10827   const BuiltinType *BT2 = T2->getAs<BuiltinType>();
10828   if (!BT2)
10829     return false;
10830 
10831   BuiltinType::Kind T1Kind = BT1->getKind();
10832   BuiltinType::Kind T2Kind = BT2->getKind();
10833 
10834   return (T1Kind == BuiltinType::SChar  && T2Kind == BuiltinType::Char_S) ||
10835          (T1Kind == BuiltinType::UChar  && T2Kind == BuiltinType::Char_U) ||
10836          (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
10837          (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
10838 }
10839 } // end anonymous namespace
10840 
CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr * Attr,const Expr * const * ExprArgs)10841 void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
10842                                     const Expr * const *ExprArgs) {
10843   const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
10844   bool IsPointerAttr = Attr->getIsPointer();
10845 
10846   const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
10847   bool FoundWrongKind;
10848   TypeTagData TypeInfo;
10849   if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
10850                         TypeTagForDatatypeMagicValues.get(),
10851                         FoundWrongKind, TypeInfo)) {
10852     if (FoundWrongKind)
10853       Diag(TypeTagExpr->getExprLoc(),
10854            diag::warn_type_tag_for_datatype_wrong_kind)
10855         << TypeTagExpr->getSourceRange();
10856     return;
10857   }
10858 
10859   const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
10860   if (IsPointerAttr) {
10861     // Skip implicit cast of pointer to `void *' (as a function argument).
10862     if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
10863       if (ICE->getType()->isVoidPointerType() &&
10864           ICE->getCastKind() == CK_BitCast)
10865         ArgumentExpr = ICE->getSubExpr();
10866   }
10867   QualType ArgumentType = ArgumentExpr->getType();
10868 
10869   // Passing a `void*' pointer shouldn't trigger a warning.
10870   if (IsPointerAttr && ArgumentType->isVoidPointerType())
10871     return;
10872 
10873   if (TypeInfo.MustBeNull) {
10874     // Type tag with matching void type requires a null pointer.
10875     if (!ArgumentExpr->isNullPointerConstant(Context,
10876                                              Expr::NPC_ValueDependentIsNotNull)) {
10877       Diag(ArgumentExpr->getExprLoc(),
10878            diag::warn_type_safety_null_pointer_required)
10879           << ArgumentKind->getName()
10880           << ArgumentExpr->getSourceRange()
10881           << TypeTagExpr->getSourceRange();
10882     }
10883     return;
10884   }
10885 
10886   QualType RequiredType = TypeInfo.Type;
10887   if (IsPointerAttr)
10888     RequiredType = Context.getPointerType(RequiredType);
10889 
10890   bool mismatch = false;
10891   if (!TypeInfo.LayoutCompatible) {
10892     mismatch = !Context.hasSameType(ArgumentType, RequiredType);
10893 
10894     // C++11 [basic.fundamental] p1:
10895     // Plain char, signed char, and unsigned char are three distinct types.
10896     //
10897     // But we treat plain `char' as equivalent to `signed char' or `unsigned
10898     // char' depending on the current char signedness mode.
10899     if (mismatch)
10900       if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
10901                                            RequiredType->getPointeeType())) ||
10902           (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
10903         mismatch = false;
10904   } else
10905     if (IsPointerAttr)
10906       mismatch = !isLayoutCompatible(Context,
10907                                      ArgumentType->getPointeeType(),
10908                                      RequiredType->getPointeeType());
10909     else
10910       mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
10911 
10912   if (mismatch)
10913     Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
10914         << ArgumentType << ArgumentKind
10915         << TypeInfo.LayoutCompatible << RequiredType
10916         << ArgumentExpr->getSourceRange()
10917         << TypeTagExpr->getSourceRange();
10918 }
10919